Jason needed to shed the armor as much as it made him look unique. For a new bladed weapon he gets to personally test (probably a little too eagerly), he needed as much mobility and freedom of movement as possible without streaking. His boots are gone and like his BattleTech image is barefoot.
The weapon, by the way, is a plasmacutter. A take on the traditional chainsaw, the plasmacutter is the next generation of both wood-cutting and steel-cutting.

All incarnations of Jason Pryde (C)  prdarkfox