Rank Up Advice

DRTO

Been sitting on 3 t5b for some time now cause pretty stuck on who I want to rank up so need some help on who you think the best option would be. Content wise I have yet to start 6.3 but plan on starting soonish. Been considering Falcon but not sure how important his sig ability is.

Sarvanga1_

Ghost

Edwxn

Archangel