i give props for the effects and i bet this did took ya awhile to create such an idea. But in my opinion this really shouldn't go with the engie of course.
At first, i immediately thought it was for the pyro -
(but not even i didn't like how this was turning out to be) but for the engineer? this can't be. I know you must hate this coming from me but you need to hear from the community about your idea(s).
1.) (simple) Engineer doesn't have the element of fire.
2.) In the game, the pyro can destroy buildings so it would be a bit confusing on why it would fix friendly buildings.
3.)Theirs a wrench that the Engineer has. He can use it.
4.) (Lastly) I don't know if this will be put into TF2, but if it does then i'll be damned.
------------------------------------------
I know it's not just me who's thinking nay, some are saying yay for it.. but for me i think this is a nay.