I feel like tailgunner was an attempt at a firespray fix. Problem is with only one crew slot tailgunner isn't necessarily the best option usually.
I think a good fix would be a new title or mod that gives you an extra crew slot, an illicit slot, and cost -2 points.
This does several things. It lowers your cost by 2, gives imps access to illicit, and gives more options by having the 2nd crew slot. Now tail gunner can be more auto include as you still have a crew slot free.
Also imps can use it as a Palp carrier which would definitely help it see more use again.
One final note about tail gunner. It's a LIMITED upgrade. Even though only two ships in the game currently can use it and neither have multiple crew slots. Kinda makes me think that extra crew slot for the firespray is coming someday soon...