The armor should be a lot better than simple impact armor, considering the nature of Mando Beskar: http://starwars.wikia.com/wiki/Mandalorian_iron
Beskar armor was still pretty heavy, so a move subtraction would probably be appropriate there, but it's really pretty much negated by their jet packs.
Also, you might want to stat out the rockets from the jetpacks. Your call there.
What the hey. This is something I've thought through before, though not in regard to the weeny Death Watch Mandos that Lego is replicating. Here are a few more uniquely Mandalorian options to consider:
Beskar-forged war blade
-Counters energy blades'
-Single-edged, fairly hefty. Good for bludgeoning.
Beskar-weave gauntlets with a specialized reactive fabric to allow the wearer to crush most holdable things... notably throats and body armor
-Counters energy blades.
-Could be used for a pretty deadly melee attack, if the user isn't holding a weapon.
-Includes targeting optics, 360-degree vision, temporary air supply, com unit, and other nicknacks.
And of course, the armor is modular, to allow for toys like wrist-blasters, flamethrowers, smart-cord launchers, minirockets, and the ever-popular pack-mounted antipersonnel rocket.
The stats I used for Boba Fett, hands-down one of the best mandos around, for a three way fight with Master Chief and a 40k Marine can be found here: http://www.brikwars.com/forums/viewtopi ... 85c60ec7fa
These are a bit, no, ridiculously overpowered for trooper fodder though, since the whole point of that particular battle was to let three god-like heroes go at it (also, I was using some custom rules for concussive force and the like. Beskar can stop a lot, but you can still be turned to jelly inside your armor if enough force is applied.