I love using the assault shield it's alot of fun, but it's too easily bybassed and there are some irregularities I will explain.
Firstly a shield bash should be a one hit kill like any other melee attack. Trying to hit someone twice is more difficult than it sounds when they are trying to knife you back. Especially when you need to be crouched to make the shield as effective as possible from incoming fire. Piling on to this you can knife people with an assault shield in the front if you're slightly off centre. Only direct front attacks are blocked. It should be 180 degree melee protection to the front. Or at least 90 IMO.
Secondly the shield can block all explosives to the front including rc.xd's but if you get stuck with a crossbow bolt or semtex on the shield you die, doesn't make sense to me.
Thirdly. in general the shields protection needs to be more forgiving. You shouldn't be able to hit a millimetre of a shield users foot with an smg from a fair distance away.
To summarise players should truly have to flank or get above a shield user to take them out. As much as it can be fun it does get annoying quick because they're too easy to bybass.
And a note to anyone with a shield user on their team....SUPPORT THEM. They're using it to draw fire, they're never going to get epic kill streaks with it Too many a time I'm left with my dick swinging in the wind because my team thinks domination is team deathmatch.