Vials and pills are official as of Aeria GunZ, onehit nades are an ancient private server idea that has hung around. I think the EX launcher should be removed from the game too, but as far as like custom rate automatic weapons goes that's fine to me. Nobody at a high competitive tier is complaining that hotshot is too OP, most of these other things are novelty. However the mines and EX grenades to me are on a level that disrupts high level gameplay with little to no skill involved. It is cool to have off meta options but these " disabling " items and weapons need to go. Anything that may knock you to the ground, or gives you a flip effect should be removed. Only melee weapons should be able to have that effect, and if you want CC then melee weapons should be your best and only option besides the standard rocket launcher.
When I say competitive I mean any gametype that gives XP. Deathmatch, TDM, anything. The fact that they are not allowed in clan wars ETC speaks to mines poor impact on the quality of gameplay. I agree it's an opinion based thing, that's all I'm here stating.