I'm sure this isn't unpopular, but it wouldn't hurt if the Move Reminder was found earlier than at the League's doorstep. I wouldn't want to see being able to learn later moves now go away, and recognize that option being earlier would be VERY unbalanced, so... why not have two Move Reminders? A young one about midway, and their grandma at the League who's more knowledgeable and thus can teach the moves a Pokemon has yet to learn. (and potentially the pre-evolution moves they could have learned had they not evolved)
That or have the Move Reminder be midway in the game, when first encountered he can only re-teach moves already learned, but after getting the 8th Badge/whatever before facing the League you can go back to them (or they'll move to where the Pokemon League is) and they'll now be able to teach your Pokemon any move it can possibly learn.
I'm not sure if the games go through the lengths of informing you why you'd want to hold back evolutions (some exclusive moves and moves being learned earlier), and so they should say that stone evolutions mean you miss out on some useful level up moves.
The games really need an in-game knowledge databank which at least hints when there is something like that to discover, so players can search for Easter eggs without trying in vain while still retaining some element of surprise. If only the Pokémon franchise had an element like that, a knowledge bank trainers carry on their person, it would be really useful in-game... a "Pokémon Index" or something like that...
They could have all this information be available at the Trainer School. They put it in every game but it's hardly used for anything important. Sometimes you're told/required to visit it but all you really learn from it are what the status ailments do. In addition to that they could have a classroom/book which tells you about how certain Pokemon evolve, useful moves they get earlier/only in their pre-evolved form, how certain moves and Abilities can work together, IVs, EVs, stats Natures effect, how much of a buff/debuff the stage increases/decreases do, how certain types have additional traits to them (I would suggest also having the Type Chart but that's something you should be able to call up any time via the Pokedex), etc..
Going back to stone evolutions
Some stone evolutions do actually still get some moves after evolving too. For example, Victreebell gets leaf tornado on evolution, leaf storm at level 32 and leaf blade at level 44. Bellossom gets four moves on level-up, but at very late levels. This is exactly what Pikachu315111 described. The system would be fine if the devs handled all stone evolutions this way. Giving all of the stone evo's a move on evolution is an especially good way of making the trade-off mechanic interesting and balanced at the same time.
Also another thing they should do is upon evolving maybe give these Pokemon a decent move in case someone does evolve them early. Using the Fire Stone evolvers as an example, give Flame Wheel to Arcanine & Flareon (later levels they can learn Fire Fang & Flare Blitz) and Flame Burst to Ninetales and Simisear (later levels they can learn Flamethrower & Fire Blast). While not all that powerful in the long run, at least it's something they can use to start out with.
Players should know how to take care of berries. They don't need to know fancy formulas, just that they need to be told that they should water the plant once per each growth stage of the berries, and any more times is unnecessary. I remember wasting time watering berries so much because I was unaware. Growth times don't have to be told, though, players should be able to figure that out.
I'm mixed on how complicated they should make Berry growing. I like the idea that if you take care of the Berries you'll be able to get more Berries, but don't like if you forget to pick them they die (though at least the berry replants itself). I do like they now have all the Berry planting happening in one location, so maybe they could do something where you can either take care of the Berries yourself or can hire a gardener to grow the berries for you (but you'll only get the average amount of Berries). Also they should have a way for you to check on your Berries progress, like the Berry Growing app for the Poketch.
If shift didn't tell you what the next Pokemon was, the only time I think you'd want to shift is if your Pokemon is running low on HP or statused. I just don't think that justifies the constant prompting otherwise.
In that case players who get annoyed with it will turn it off. However I think by having set not tell you what Pokemon is coming up next might help young players learn to "predict".
Say if your active Pokemon is a Fire-type. Unless the trainer you're battling is a Type Specialist like a Gym Leader, if they have two or more Pokemon left they'd send out the one which is best for facing Fire-types. Fire is weak to Water, Ground, and Rock, so if you have a Grass (or even Water) type you could start the next battle off on the advantage. Now, of course you may run into situations where you predict wrong and turns out they send out a Poison-type because they don't have a countering Type. But that's the risk you take on switching, it's no different then when you start a battle and your opponent sends out a Type the first Pokemon in your party is weak too.
And there's also other factors like if your active Pokemon is low on HP or you just want to spread experience around.
I think the best choice for this is to outright ask the player at the beginning of the game if they want to play on Shift or on Set. It's likely many players don't even KNOW this option exists, and think Set is only possible on PvP and Battle Facilities.
Yeah, but also keep the option in the menu and the game should tell you if you change your mind you can change the setting in the options. Maybe also have the Trainer School explain that too.
When people are asking for more post-game, I think this is what they're wanting. Another option to continue playing without the insanely difficult Battle Whatever grind, or repeating what few repeatable challenges the games have to offer (the E4 over and over again). In that respect, White Treehollow/Black Tower was great, as those challenges had a clear end point with a sweet reward, and building up Join Avenue was very fun too.
I agree they should bring back something like White Treehollow/Black Tower but do more with it. After you complete it, while you can always challenge it again, it does feel like you're doing the same thing again as at that point the story is done. Maybe they could do something like have little post story campaigns you can do that tells a story and gives you choices which you can replay over and over again. Like have your player join a Escape Room/LARP/Dungeon & Dragons-like group. And while the base game will have a batch of stories to play though, they could add even more through DLC (free of course, this is something to keep the player invested in the game).
Everyone hates the "1 save slot" restriction in Pokemon games.
I think upon completing your initial playthrough they should unlock a second save slot that lets you replay the game (and maybe even have it give New Game+ options but that's an entirely different discussion). And when you complete that playthrough you can then send Pokemon (and maybe certain items) between the save slots (that way you can keep on restarting the 2nd save slot yet still keep the Pokemon you trained in it by sending them to your 1st save slot game).
But as said, with the Switch allowing for different accounts that'll probably be a non-issue (unless they make it one save slot per console). When the games are handheld it makes sense, handhelds are personal devices thus having the one save file encourages players to trade & battle each other. However since home consoles are used by many members of the family I say makes sense for each account on it to have its own save file. It will just mean you can't trade with the other version without using the GTS.
So that brings me to the opposite, which is also an unpopular opinion of my own. I liked the key system in B2/W2. Yes, the execution could have been better, but it was still fun for what it was. I loved Memory Link, it made B/W and B2/W2 feel a lot more connected. Getting both Black Tower and White Treehollow in both games was tons of fun.
I agree, nothing wrong with the Key System itself, just some of the things they did with it was REALLY stupid. Notably the difficulty settings, they shouldn't be keys at all but standard options from the start.
LOVE Memory Link, really what makes Gen V such a unique generation and only frustrating they haven't done something like this in Gen VI (which they skipped having a 3rd version/2nd paired games) and Gen VII (which second paired games was just a slightly altered version of the initial versions). Memory Link made it feel like what you did in BW mattered, there was a purpose to those games and the relations and choices you made in them.