I don't know if Greedo needs a buff so much as a rework. He's viable as it stands. I've got 7* g11 which I run on a BH team with B2 and Greedo routinely double taps for 22-24k dmg. His speed is pretty good, easily >205 with mods and that doesn't account for speed boost and TM gain from Boba lead. That being said, he could use some tweaks.
So his basic is legit. His Bombs are okay. Obviously BH thrive on detonations, so you've gotta keep those. I like the OP's TM gain per successful bomb hit, or they could do speed up on him like they have with Zam's bombs. I don't really like the OP second clause of rework, which is convoluted and likely a programming nightmare.
His unique is not bad (although I swear from 200+ battles that it doesn't actually give him increased crit chance). I'd probably boost his multi-attack chance to 75%, and throw in a Zeta. A fun twist could be self-cleanse and gain 30-50% TM whenever a bomb detonates. He'd go a lot.
His leader is worthless, and objectively he's not a big enough character to warrant a leader power. I think he should get another attack (possibly AOE dmg or a special debuff). BH need a dedicated dispeller (don't give me that "Oh Boba' execute is all the dispel you need" garbage), so maybe he could have a targeted or AOE dispel. Alternatively maybe a low damage AOE that applies defense down to all enemies, or a targeted powerful debuff like deathmark. I mean he was able to hunt down Han's planet-hopping bum before getting blasted in the alien junk.