is there a need for cresselia to have both psychic and psyshock as potential moves? i've already experienced myself or witnessed a cress losing a calm mind war due to carrying psychic over psyshock, and it just seems pretty silly that it would be able to have psychic in that situation when psyshock is just as good in most situations with the added benefit of being able to do better vs other calm mind mons. If there isn't a great reason for psychic to be kept as a potential moveslot, i think it would make more sense to have psyshock as its only stab
So you ask this, and I got curious how often psyshock is preferable to psychic. Its not often that you're really boosting up beyond +2/+2, and typically if you get there you've already won anyway. So I think the real question here is "is the tradeoff from winning CM wars worth the 15 bp reduction in the cases where you are not boosting to +6." Let's do some math and see where this takes us.
I may be off by one or two here, but by my count 26 mons have sets with calm mind. Of those 9 only have it some of the time, reducing the frequency of facing a foe with cm by a little. To account for probability, lets call it 4 mons' worth. And lets just assume every mon that has cm will get it, since typically that's the case with how Setup Sweeper roles work (though there are cases where mons have cm and dont get it). We can mostly discount mons without recovery, since cress would just wall them out with moonlight anyway. So we concern ourselves with the 13 mons with recovery moves that would constitute cresselia entering into a cm war in which psyshock would be superior. Well, make that 10, since Umbreon and Spiritomb don't care about Psyshock vs Psychic (and Arceus-dark, but the odds of getting any one arceus form are annoying to math out so I'll ignore him) and Cresselia, because whatever change we make would affect your opponent too. Of those 10, theres (very roughly) a 50% chance they roll the species and the set with CM and recovery. So lets make the math easy and say there's 5.
5 mons' worth of CM+recovery sets, and 276 unique species in the format
The odds of your opponent having at least one pokemon that would be hit harder in a cm war by psyshock is 1-[(271/276)*(270/275)*(269/274)*(268/273)*(267/272)*(266/271)].
5 mons' worth of CM+recovery sets, and 276 unique species in the format
The odds of your opponent having at least one pokemon that would be hit harder in a cm war by psyshock is 1-[(271/276)*(270/275)*(269/274)*(268/273)*(267/272)*(266/271)].
Obviously in an actual game there will be many, many times when either cress or the rival CMer get offed before they square off in their epic struggle, so I'll ballpark 5-8% of games with a cress will see a CM war.
If we add psyshock to cress, we can either add it as a 50/50 between its psychic stabs or commit fully and remove psychic. Knowing that in 8% of games there is a possibility of entering a CM war, do we allow for the other 92% of games to see a 12% reduction in base power versus every other target?
Personally, I'm not convinced, but we can try and put psyshock as an option and see where the winrates go. In all actuality, it probably won't make all that much of a difference.
(And incidentally, if my logic holds, we actually should consider swapping Slowbro over to Psychic, since it also can enter in a cm war, but currently is psyshock-only)