Choose two – Untap target creature and gain control of it until end of turn. That creature gains haste until end of turn; or sacrfice a creature you control. Flameborn Command deals damage to target creature or player equal to the sacrificed creature's power; or destroy target artifact. If it was destroyed, Flameborn Command deals 5 damage to its controller; or up to three target creatures an opponent controls cannot block this turn.
Whoa. Way too many things on one card!
And.. can I use those first two abilities together to turn this into an expensive way to kill a creature?
Yes, you can, like you could with Grab the Reins, for much the same effect. I agree that sadly this is too wordy, compared to the original Incendiary Command cycle. You can save two words because "sacrifice a creature" doesn't need "you control" after it, but it's still got way too many words.