I haven't seen any mention of vaporeon in rby ubers and wondering if it has any viability / why the concept below isn't viable.
Haze
Acid armor
surf
rest
Haze is the primary move that could give vap a niche in this meta where it isn't outclassed. Basically it would be used in conjunction with vaps special bulk to come in after a KO from a 999 special mewtwo, tank a hit (assuming mewtwo is unparalyzed) and haze off the amnesia boosts. It would be kod next turn (select haze again in case mewtwo tries to boost instead) allowing a "counter" to come in but now with the boosts removed, which could obv be the difference in stopping a game ending sweep.
Haze could also be used on slowbro at +6, esp since slowbro all carry surf here plus vap is faster so vap would only be taking a +0 surf. but I'd think stopping a mewtwo sweep is more important.
Acid armor, rest, surf is enough to force physical lax to switch out (or selfdestruct), it also gives vap a chance against paralyzed offensive mew maybe 25-30% ish I'm struggling a little w the calculations (both would be reliant on hax to break through). (Sd/eq/hbeam unparalyzed mew still needs hax but is almost guaranteed to break through before running out of pp since any hbeam crit and sometimes eq crits will be enough to break rest loop, and vap can never break through soft boiled without paralysis other than stalling it out of pp.)
Ice beam could maybe be an option over surf, but vap can never attack mewtwo which is what you usually want to freeze, fishing for freeze against unparalyzed mew isn't any easier than hax to break through paralyzed mew plus only surf can pp stall soft boiled, and the extra damage does make a difference against snorlax (and switchins other than chansey.)
there are obv definite problems, vaps offensive presence is zero against most of the meta game (mewtwo slowbro ofc, and rly almost anything with any form of recovery), struggles with zapdos and gengar, neutral surfs will do something to the ou pieces but it's rly never going to be a real offensive threat. so very defensive/stall oriented, probably even more than most chansey.
rly the biggest problem I see rn is it can't lead at all and makes it hard to fit a sleeper on your team. since vap is so defensive the best option for the team is probably sing chansey, but chansey probably cant lead. idk im rly bad with actual in battle tactics so maybe someone else could address that (solution or if that dooms vap).
(there's also a possibility with hazing mewtwo that opponent could instead switch mewtwo out for a sleeping poke to remove the status with vaps haze. but since haze is an emergency stop to a sweep i don't rly see that as a serious problem, plus if ur sleeper is still alive you can ofc sleep something else. hazing off freeze is also not rly a concern since then you could get another chance at freezing mewtwo)
Despite its issues, vap with this set is the closest thing to a snorlax counter (which will rly help w predicting lax self-destructs), has some use against both mews, and also can stall slowbro. no OU pieces other than snorlax, slowbro and chansey can do anything close to that.
the biggest issues for vap in OU are its limited attacking moveset and second it's lack of recovery, so it's outclassed there by Lapras and esp starmie. the first doesn't matter in ubers rly at all (e.g. compare to chansey rarely using thunderbolt) and acid armor plus vaps special bulk makes rest viable recovery in some scenarios. and water typing is better in ubers i think bc of all the ice type attacks.
unlike in ou, haze rly isn't a gimmick bc of the importance of amnesia / mewtwo. Vap is also the only user of acid armor or barrier besides mewtwo that's at all viable, and while physical defense is obv less important than special, being able to switch in to snorlax if needed and survive setting up aa unless hax seems pretty valuable.
idk am I rly badly misanalyzing something?
Haze
Acid armor
surf
rest
Haze is the primary move that could give vap a niche in this meta where it isn't outclassed. Basically it would be used in conjunction with vaps special bulk to come in after a KO from a 999 special mewtwo, tank a hit (assuming mewtwo is unparalyzed) and haze off the amnesia boosts. It would be kod next turn (select haze again in case mewtwo tries to boost instead) allowing a "counter" to come in but now with the boosts removed, which could obv be the difference in stopping a game ending sweep.
Haze could also be used on slowbro at +6, esp since slowbro all carry surf here plus vap is faster so vap would only be taking a +0 surf. but I'd think stopping a mewtwo sweep is more important.
Acid armor, rest, surf is enough to force physical lax to switch out (or selfdestruct), it also gives vap a chance against paralyzed offensive mew maybe 25-30% ish I'm struggling a little w the calculations (both would be reliant on hax to break through). (Sd/eq/hbeam unparalyzed mew still needs hax but is almost guaranteed to break through before running out of pp since any hbeam crit and sometimes eq crits will be enough to break rest loop, and vap can never break through soft boiled without paralysis other than stalling it out of pp.)
Ice beam could maybe be an option over surf, but vap can never attack mewtwo which is what you usually want to freeze, fishing for freeze against unparalyzed mew isn't any easier than hax to break through paralyzed mew plus only surf can pp stall soft boiled, and the extra damage does make a difference against snorlax (and switchins other than chansey.)
there are obv definite problems, vaps offensive presence is zero against most of the meta game (mewtwo slowbro ofc, and rly almost anything with any form of recovery), struggles with zapdos and gengar, neutral surfs will do something to the ou pieces but it's rly never going to be a real offensive threat. so very defensive/stall oriented, probably even more than most chansey.
rly the biggest problem I see rn is it can't lead at all and makes it hard to fit a sleeper on your team. since vap is so defensive the best option for the team is probably sing chansey, but chansey probably cant lead. idk im rly bad with actual in battle tactics so maybe someone else could address that (solution or if that dooms vap).
(there's also a possibility with hazing mewtwo that opponent could instead switch mewtwo out for a sleeping poke to remove the status with vaps haze. but since haze is an emergency stop to a sweep i don't rly see that as a serious problem, plus if ur sleeper is still alive you can ofc sleep something else. hazing off freeze is also not rly a concern since then you could get another chance at freezing mewtwo)
Despite its issues, vap with this set is the closest thing to a snorlax counter (which will rly help w predicting lax self-destructs), has some use against both mews, and also can stall slowbro. no OU pieces other than snorlax, slowbro and chansey can do anything close to that.
the biggest issues for vap in OU are its limited attacking moveset and second it's lack of recovery, so it's outclassed there by Lapras and esp starmie. the first doesn't matter in ubers rly at all (e.g. compare to chansey rarely using thunderbolt) and acid armor plus vaps special bulk makes rest viable recovery in some scenarios. and water typing is better in ubers i think bc of all the ice type attacks.
unlike in ou, haze rly isn't a gimmick bc of the importance of amnesia / mewtwo. Vap is also the only user of acid armor or barrier besides mewtwo that's at all viable, and while physical defense is obv less important than special, being able to switch in to snorlax if needed and survive setting up aa unless hax seems pretty valuable.
idk am I rly badly misanalyzing something?