The MW5 trailer battle took about as long as most MWLL battles do now (maybe even a little longer if you used the same weapons and armor in MWLL for each mech) and a single PPC shot took out a huge chunk of that Atlas
The drawback to this amazing weaponry is accuracy. Those mechs could barely hit each other at 40 meters (I know there was a lot of shake from enemy hits as well) and from the few things I've read from what people posted about MW books, that's the way it generally should be
MWLL mechs can shoot a fly out of the sky at 800 meters with no issues, and pay for it by being equipped with ER staplers
Higher damage=/= equal shorter fights, something else just has to give, and with the dev's hate of randomness, I'll have to wait for MW5 to get the feeling of power I want from mechs
Both versions (MWLL and MW5) are fun and tactical, but you just can't have high damage in MWLL because of the high accuracy