I’d go for medium, because small are usually light weapons and weak, but fast. While heavy are big targets slow and big guns. While medium genrally combine average weapons with a normal hit rate etc…
Preferably I love the rambo concept, being able to run into 3 guys and manage to take them down, gives a great feeling.
(I base my opinion on team fortress 2 where you have a heavy, scout and medium classes)
What does sway my opinion is if you get a compensation, like soldiers are slow, but can use rocketjumping to speed up, but do loose health if doing so, and it’s not the easiest thing to do.
tokamak, not sure what you mean with heavy classes not being abele to rely on twitch movements, i actually find that twitch movements can make the class even more deadly.
Like in ET jumping from a corner charging and then at the last minute checking where your target is redirecting you aim before the bullet flies.
Or with the heavy weapons guy in TF2 jumping around a corner and getting your mouse on your enemy asap, or killing an enemy and then doing a 180 and killing the guy behind you.
What I absolutely hate is when games mess with your mouse. (Bioshock) in bioshock when you come into a new level your mouse is sluggish and takes a few seconds to flow again, also in general gameplay I find it sluggish.
This compared to ET where the bullets fly where you point (little spread) so the first to aim is the first to win.