he's a pretty nonchalant guy when we first meet everyone, he can only run in short bursts and he has a potbelly; so a pretty shitty speedster is what we're supposed to get from him. he becomes more assertive and active over time and dies a hero's death deactivating or removing (I forget) the bombs for everyone else but he couldn't get his in time. Tom Taylor's Suicide Squad is honestly the best suicide run in a LONG time (and I actually am a fan of some of their other incarnations), definitely was a stealth book for the revolutionaries but it worked great as a Suicide Squad team regardless. it's short, effective, and to the point.
the black Lightning is new, they were white/light blue before he died.