sneaky pete, tick, janus, jaguar, better veh arty, liche, abductor, better T3(not that much after recent core buffs but still),cheaper spies and finally EMP bombers.
while core op units are only shurikens and fiends probably, T2 figs difference not that important imo, because T2 airlab is more versatile and better than core one.
both factions have good units, and currently thread is not about that.
This thread is about EMP and i say both factions have op EMP shit:
EMP bombers for Arm, Shurikens for Core and both spybots.
As i said before i think slow and massive units have to have great stun resistance, so lighter units are easier to be stunned than big units.
I'd suggest adding 50-90% emp resistance on slow T2 units like fatboys, tzars, mammoths, sumos, zeuses etc. Keep emp only good against faster units (btw this will make arm jaguars even more op compared to fiends since they have builtin AA)