Also, a couple assumptions; Mechs have stronger comm systems than other vehicle types and are useful links to the rest of a planet's comms in a situation where satellite systems are down. There are vehicles that provide command and control functions way better than a mech not designed for it (though Phoenix Hawks and Wolverines have comm and sensor systems designed for it -- actually, they have the same systems down to make and model) but mechs usually are doing that job in almost every situation, especially at a lance level.

Also assuming a degree of data synchronicity among lances. That's more of a house rule, but the way I see it, they share some targets, though this is vulnerable to a good ECM system. 

Thirdly, the mechs carry UAV's and neurohelmets can be tuned to work better with a given class of weapons -- processing power devoted to laser, ballistic or missile weapon optimization.

SRM's, LRM's and AC's can be loaded with special munitions, except for UAC's whose chambers are designed for rapid feed and require, lest reliability suffer even further on rapid fire, standard munitions. We are going to tweak the timeline to admit these munitions into play for versatility and fun.