Can you really sleep talk with jolteon? Can you? Would you? Ok, then it's not worth mentioning. Same argument to retarded stuff like Kingdra. Vap's defense is underrated, maybe you're overrating it, but that doesn't make it any less formidable. Boo-hoo, it doesn't survive a DE off 366 after taking double Thunders off 298. So what? Did you expect it to?
Smeargle's the best passer. Jolteon runs into the same problems whether it's passing Agility or Growth: Snorlax and Raikou. Vap forces plays that Suicune doesn't; they're not comparable at all. "Really fast hard hitting electric"; sounds redundant.
Vap has 2 soft walls at all times; so does Jolteon. It's an electric after all.
Jolteon has less random walls, in the sense that it'll take 2 consecutive thunders, while compromising 2/3s of his life taking the "randoms" down (ttar, machamp, heracross). And there's still Egg vs Steelix vs wak/nido/rhydon coverage that you have to choose between. And can't forget lax. And the odd Raikou still roaring. What about Blissey?
Surprise wins games. Of course. But what surprise doesn't do is change a meta, which is what you're proposing. Jolteon is a better off pitch than Vaporeon, who kinda defines the meta in itself. This is the Charizard/Quagsire vs Skarm/Suicune comparison; Charizard/Quag wins games, but you can't even begin to consider a meta without Skarm/Cune (whose usefulness is downplayed by the fact that everyone considers them when building a team). Vaporeon's usually accounted for, Jolteon isn't.
I don't feel that Vaporeon is as impactful on the metagame, sorry.
Now you're just trolling. Like with HP electrics, you don't technically have to go out of your way and "prepare" for it, so to speak, if you don't want to or can't spare the room. Does that make it any less "impactful"? Nah.
Anyway, if Jolteon is better, then use it. Prove it. You don't have to argue for it. If it's really good, people pick up on it, you shouldn't have to justify something that's truly good anyway.
EDIT: @Electro Gypsy: And of course I send mixed signals. There's two sides to every pokemon. And when talking about how to use certain things, which side would you want to hear?
I'm merely pointing out that Marowak falling behind Dragonite/Forretress isn't exactly a surprise, and it really shouldn't be. Having said that, does that make Marowak a bad pokemon? Not really. Because Dragonite/Forretress are great pokemon in their own rights. If something is an inferior Snorlax, does that make it a bad pokemon? No. Now I wouldn't even call Marowak "inferior" to Dragonite/Forretress, but just the fact that its "lesser usage" doesn't throw up any red flags.
Now, likewise, Dragonite has upsides and downsides too. It threatens everything readily, comes in on spikes, etc etc wins some games flat out. But on the flip side, Dragonite falls short of some pretty important damage thresholds, and is very suseptible to bad luck. It CAN'T win some games, etc etc, but these are things you have to deal with yourself. All pokemon have downsides. Curselax has coverage problems, and there's no way around it. Drumlax is a bitch to play. HP electrics sometimes is setup bait for... Jolteon, which is pretty gnarly if your team's weak to it.
Furthermore, Vaporeon has problems as well. 8 PP only goes so far (but ST helps in that regard). It's bulky enough to take quite a few hits (50/50 chance to survive 2 jolteon tbolts; 50/50 to survive 3 egg giga drains, 3 nido thunders, 3 lax returns; takes 3 lax bslams easy, 3 starmie tbolts easy, takes 2 megahorns, etc), but NOT enough to take a couple other ones (not enough for zap's tbolt, not enough to take 2 dnite thunders and a de, not enough to take gengar's tbolts, etc). Depends how you want to argue it. Jolteon has great coverage, and poor coverage, depends on how you want to look at things. Guaranteed to survive a Nido EQ (but that goes away when HP is factored in), 50/50 taking 2 snorlax returns (again, changes with HP factored in).
I'm careful not to point out that Jolteon "sucks" in any way. Vap's better, but that doesn't make Jolteon bad. With Vap, you're looking at top 10 consistent material, whereas at best, Jolteon's one of the best "surprise" pokes in the game, but by definition, that makes it an "overall" worse pokemon. Something that's countered and accounted for consistently team after team that still performs is probably better "overall" than something that relies on... well, surprise. Analogy: if you're "spoofing" and creating new accounts to get "different" battles (which you do, so you can relate to this example), then naturally people play a bit differently against you, for better or for worse. This is undeniable. There's NO WAY you would play against a random on PO with the same style/concentration/prediction/thinking/whatever as you would if you were playing someone in this thread. That just doesn't happen. I know for me personally, if I can't recognize the person I'm playing, I'm going all out reckless plays to win faster (since I expect to win against a nobody obviously), and because against any bad player, it's far easier to recover from any run of bad luck or misprediction than against someone who knows what they're doing. That wouldn't be the case if I were playing someone I knew and respected to a degree. Knowing the player is just as important as knowing the team.
Again, if Jolteon truly good, it doesn't need to hide behind the shadows and prey on unsuspecting teams/matchups/metas. Jolteon technically "can" do that, but it has an unproven track record of "doing".