I would actually prefer not to have a balancing system where one faction is preferred over another for roams. We do take green and yellow mechs on roams if that's what people can use, but most of the time people don't want to, and the ones who do always complain about being slower than everyone else. Or get laughed at for eating kain dust and missing out on the trophies.
Missile bots may shine in intrusions, but it seems a bit hard on them since we get to participate in those less often...and where does that leave poor old laser mechs?
But given that kains are close range, I don't know how you would change them to make the artemis and tyrannos an equally popular option as a roam mech. Maybe reducing the speed just a teensy bit to make the gap between them closer?
This is why I don't like systems with that use speed to balance things - it's simply too crucial in open world pvp.
(As an aside, seeing as I hear Dev Alf wants to make base detection and masking attributes different for each faction, I bet he wants to give kains higher masking and lower detection values. Which would make them even more popular for roams...)