I am levelling up my MCH now and I can tell you that it's a class where I am constantly looking at my hotbar.

I have to look at my ammo, my procs and keeping an eye on any other cooldowns. Much like how healers look at the party list a lot, looking at my hotbar and buffs all the time distracts me from the actual fight.

So I have some simple ideas to the UI to make MCH a little easier to keep track of.

I think it would be really nice to have an ammo bar to keep track of our ammo. The bar should be a yellow bar split into 5 segments to represent our ammo. There should also be a 'draining' or ticking horizontal bar on the bottom which repesents the duration of the ammo (so think of it as a cast bar, but for duration of the ammo buff).