Droids are too slow and squishy to do anything without Jawa engineer, the HK lead is too reliant on crits to succeed, and in general they're too reliant on debuffs. Even R2s burning can get quickly cleansed by savage in a zaul lineup and then you're back to square one.
I hope someone proves me wrong, but I'm just a little pessimistic. That being said, if you do want to try this I would recommend a grievous lead over HK. He hits harder than the -20% crit damage the other team gets will help out with surviveability