Malak would just look like he did in that korriban cave, yep thats right a bald idiot with random tatoos, and very tall :ph34r:
I could see "The Mandalorian Wars" as a RTS, following the same style of combat of EaW (but of course better, more realistic land battles <_< )
and in campaigns you can either choose republic, or mandalorians
Mandalorians would just be like following them, and their plight conquering the galaxy and just taking the first beginning star systems (and you would be just fighting like the local militia, and the resistance groups, small armies ect.) and then comes the republic, yep crappy as always and you, the mandalorians give them an ass wh00ping. then there is a part in the campaign, where you have taken like all the galaxy (except a few planets) then comes mr rebellious revan 'n' malak, with their jedi counterparts kicking your asses back to dxun, and malachor
the republic would just be you fighting the mandalorians (similar to, eh whats a game, sorta like rome total war) you with a few elite units and regiments against a massive ass mandalorian army, and somehow you pulling it off with many losses on both sides ect. and like halfway through comes revan (which you get to control) then you can recruit jedi and stuff who ultimately end the mandalorians