I have opened a lot of BB-8s. Is it found in any competitive decks? I haven't seen him in many lists. What is holding the card back?

BB-8 is pretty much pure filler. His dice doesn't do anything particularly well - you're basically paying 1 (and an action each turn) to do something randomly helpful every turn. He's not 'bad', but most decks will probably be able to find something that is more helpful than him.

Also, it doesn't help that in general, supports are much weaker than upgrades. So if you want to play a cheap card that is mildly helpful, you'd probably take any available upgrades before you'd take BB-8.

I think bb-8 is to generic to be good in specific deck.

Most decks focus on a clear premiss and include cards which support this premiss. With such a tight cardspace of 30 cards per deck it is hard to find a place for bb-8 who is more generally good instead of really good in one department.

He´ll get more used when people start to move away from "pay for one upgrade and sac the rest of the hand for rerolls" game every turn and starts to use the various die- and deck manipulation mechanisms more. With three sides that are always good; Focus, Resource and the reroll+roll again for a measly one resource there´s alot of utility.