Right now there is no any practical reason to not take rifleman in common public skirmish game expect some rpg-motives or wierd fun ideas or sick flag-fencing.
Its not like this or that and balance, one option is just better for common player who needs frags, more frags and this is all he want or like. But this is for first 10 each team, who has fast loading.
So rifles not hated par se, they just feel "unfair" in overall logic -- almost nothing right now compensates this to other main classes. Also no real disadvantages for rifleman to other troops.
x2 reload time to current
less health (like 2/3 of line infantry)
weaker melee (less effective sword-bayonet)
General idea, rifleman must be complete shit in everything exept movement and somewhat slow sniping.
Thats how rifleman should be balanced in my opinion.