Not going to argue against every single point, but in general:
Gun is alrdy insanely OP. If your ACU is at front, your attention is usually there 90% of the time -> You are able to micro it. If your opponent is not Aeon and you both have gun, you can just deal free damage the whole time while your opponent can't do shit against it. Only Cybran with the stealth-upgrade can counter gun at least a bit.
Auroras have hover and way more range than any other tanks. Their whole purpose is to just defend certain points, if you make them faster no other faction has the slightest chance of pushing them.
Mercys are already overpowered as fuck. Their hitbox is broken so flak and MAA sometimes don't even hit them, once not scouted your ACU can be dead in a fraction of a second. They can be used to kill other mexes around the map or just snipe basically anything stationary if you get through. You can't even dodge that shit. Giving them even more HP makes it the most overpowered unit in the whole game since you can have them so early on. Take a larger teamgame for example. 4 players of each team fighting at front, maybe two chilling at the back. If one of them rushes mercies and if they have even more hp, the other team is never going to be able to push again
Like it can be that some of the suggestions might improve the gameplay for lower ranked people since they simply can't use all of the mechanics yet like they're intented to be used. But it will absolutely kill the balance for basically any higher ranked lobby. And balancing the game in order to improve it for only the lower ranked ones shouldn't be the goal.