He's being hamstrung by creative. You think they signed him just because he's a good worker ? There are literally a thousand "good workers" on the indies / NJPW / ROH.
But instead of letting him be charismatic they're telling us he's charismatic. Finn and AJ's unscripted promos on this match - literaly 30 seconds from Balor and like 50 seconds from AJ - are the best they've delivered in who knows how long.
Some good promos there, just two great wrestlers delivering their message.
Finn Balors "Demon" gimmick, like Bray Wyatt's "Sister Abigail" just doesn't work because they aren't particularly logical. Undertaker and Kane had similar gimmicks, but they were big, muscular, terrifying wrestlers first. Balor and Wyatt just don't have the physical presence for it.
I preferred Balor as Devitt, riding Bad Luck Fale to the ring and doing the double gun finger point whilst his jacket flashed. The Demon really hampers him, like Wyatt's gimmick does.
Sometimes I think that creative deliberately sabotages NXT stars. I think of Bayley for example, who was put in positions of having to be spontaneous on the mic, when she is a shit talker. Same with Nakamura.
I think that Alistair Black can be a big star too, if he keeps his mouth shut and is pushed like Crow Sting. Creative will probably have him cut 20 minute in ring promos pandering to the audience and making fart jokes though.
Nakamura is hanging in there, barely...