and if you wish to remove the dash as a whole maybe a shield recharge start after the decoy is deploy

If the engi is most about summoning units to fight for him (the way i like to play him) maybe a hologram decoy on a mini dash. which last 5 sec or until you fire or use other gear making it a get out of jail free card from heavy weapons. with very low HP This add the ability to act as fake bait while friendly put down heavy fire making his Shift a Support for the team and himself The decoy cannot fire or move and it HP scales 1/3 of the Engi HP. and you could make it throw taunts at the other bots for fun calling them Names