I have seen one half hearted attempt at coming up with a reasonable reason to nerf him, including some analysis of the meta. The rest is just a bunch of online warrior esque crying. People are calling Wesker top 5 in a game already full of 8 new characters and a retooled system and nerfs and buffs for every character. Chill out and think about things before you get all passive agressive with the rhetoric.
The Wesker meta is simple. He gets bodied by like 3 characters above him IF the person controlling them plays better than the Wesker player. The rest of the characters, Wesker can get around with choice assists like Plasma Beam and Vajra making unfavorable match ups into favorable match ups. He has clutch close ranged anti-air moves meaning he can some what deal with tri-dashers, his fast projectile means he can lame out lame characters like Ghost Rider or any one with a bit hit box and his teleport/air grab/command throw game means he can open up the opponent rather easily. His footsie playstyle is one of the best in the game because everything he does is relatively safe and his cr.M is untouchable by anyone who doesn't have sword normals. His health is effectively "above" average in the game because if you actually take the sum total average of all the characters in the game it's actually closer to 900K and the tournament staples characters are mostly all below 1 million. His OTG low hitting assist still remains the staple OTG of the game. His anchor game is one of the best in UMVC3 because of how quickly he kills opponents in it, it truly strikes fear in the opponent when they see Wesker at last spot despite not even being a character that should be an anchor character. Then you finally wrap it up by realizing that Wesker has the availability of all his tools at the lowest possible execution requirement in the game meaning there is no need to learn actual hit confirms with him or be mindful of approaches/footsies/pressure or even learn his advance combos because meterless baby combos with Wesker do 600K damage (while other characters can possibly do that much it's at an extremely higher execution cost).
Yes... Wesker may not have the highest damage, the best ranged normals, the best mobility, the best assist, the best anchor game, the best mix ups, the best zoning game, the best pressure... but I'll be damned if he isn't top 5 in all of them. There are very few characters in the game who have as much going for them as Wesker. The real concern of the meta is that those characters that actually do well against Wesker are amongst the lesser played characters in the game because they have other match ups to worry about. Morrigan might do well against Wesker 1 on 1, so can X-23 but their margin to mess up is WAY less than Wesker's and the existence of assists make it so that Wesker can cover up many of his bad match ups.
Now if you want to analyze system changes and what the new roster brought to the table compared to the previous game, here is a run down:
Stuff that benefited Wesker due to system changes/roster changes:
*Most top characters getting nerfed in hit stun scaling and damage indirectly buffs Wesker. Dante ALWAYS did better damage than Wesker, now Wesker does more damage than Dante on average. Wesker was one of the very few characters in the top tier who got his damage buffed substantially. Even random Phantom Dance does so much more damage now it's stupid.
*Nerfed X factor didn't impact Wesker much at all. The fact that people don't use LVL1 much anymore means they are more reliant on LVL3 XF. When Wesker has an inherent passive bonus on him that strengthens his anchor game... he basically overrides any incremental decrease in his X factor bonuses from vanilla. In glasses off XFLVL3, he has the same bonuses as he had in vanilla which were absolutely bonkers. Most other characters got their XF bonuses nerfed.
*Removal of DHC glitch benefits Wesker more than it hurts him. DHC glitch allowed lower health characters to completely dominate higher health characters because with 2 bars you could kill any character in the game. This isn't the case anymore as now you have to actually perform combos to kill higher health characters or spend a lot of meter. Wesker still has enough health where he can survive BnBs and even some DHCs, meaning his overall survivability in this game is more or less the same as before.
*Addition of Vajra assist is an unbelievable buff to Wesker. Before the characters that gave Wesker trouble were those that could dominate the air space and could mount an offense from a space where Wesker had a hard time touching. Not anymore because Vajra allows Wesker to touch that portion of the screen which he couldn't AND if that isn't enough every time Vajra connects Wesker gets a full combo off of it.
Stuff that didn't benefit Wesker:
*Meter gain nerf affects Wesker as he was one of the primary battery character in vanilla. This mostly impacts his synergy with Phoenix because not only does he have less health for meter tanking, builds less meter but he also can't use his glasses buff because he has to save meter for Phoenix. On top of this, Phoenix herself is nerfed.
*Removal of Tron Gustaff and nerf to Haggar assist nerfs Wesker. Haggar assist is still good but no more hard knockdown means that Haggar + Wesker combo isn't as deadly as before. The nerf to GTFO assist is a nerf to Wesker because this was his way of dealing with tight rushdown characters like Wolverine and X-23.
*Addition of a character like Firebrand nerfs Wesker because this is one of those characters that Wesker has trouble with "on paper". It's still going to take a while before Firebrands start appearing more often in tournaments and until people learn the match ups well. Until that happens, Weskers are still going to run over Firebrands especially with the Vajra assist that allows them to mitigate the match up against Firebrand.
There is probably a bunch of other stuff I am missing but this is the general gist of it. It is safe to say that until people start picking characters like Zero more often in tournaments, Wesker is going to run rampant and win stuff. Wesker at this point is an extremely safe and easy pick in tournaments. He is easily the most picked character in tournaments as of now and will continue to be this way for the near future.
It is completely justified to ask for removal of the sunglasses mechanic. It's not even a "tool" that is being removed. Phantom Dance also should be fixed.