Just some ideas.

Light Class:
Fairly fast; can sort of run compared to the clunking of the heavy class. Weak weapons, perhaps armour piercing capabilities but with less overall damage, and light armour. Because of the lightness also a heavy explosion or blast or impact could send it sprawling. Also quite manuverable.

Standard Class:
Moderate speed, armour, manuverability. Some fairly strong weapons; perhaps energy cannons or whatnot.

Heavy Class:
Well, what do you think? Handles slowly, but has lots of armour and additional heavy weaponary.

Additional Hover Class:
You could have a light, standard or heavy hover mech. The light hover mech wouldn't have much armour at all, if any, but it could have a big thruster for afterburns and such. Mightn't be able to fire it's heavier guns while at a high speed. The standard would again be in between the light and heavy, able to fire its big guns at max speed. The heavy would move slowly, but have the upside in that it'd be able to lay waste to anything and everything. No afterburner.


No weapon ideas yet. But a shield capability perhaps; trading off weapons for an energy shield in addition to armour. Can only fire some weapons while deployed, and speed is reduced too.