I’ve posted other suggestions for buffing the TNT mines, but I don’t think I’ve ever seen this as a suggestion:
After placing the piece of TNT, the detonator comes up in your hands, like it does currently, HOWEVER, give the option to place the detonator down somewhere (nearby). This way, it can be interacted with by another character that either belongs to that character, or someone in their party.
If its done this way, the player can set up ambushes in advance, and set them off at a strategic point in time. There’s no loss of function if that character dies then either, which is currently a major issue.
If a teammate detonates it, and gets kills, the player that set it up still gets assists, like how Engineers get points for kills with their structures.
This can also lead to useful teamwork combos where the engineers can combo defensive structures and TNT placements to really give their teammates an edge when trying to hold back enemies.
If combined with other previous suggestions, like being able to place multiple pieces of TNT with a single trigger option, it could make for some game-changing tactics. Especially in Pacific, where often times the Japanese seem to have trouble holding defensive points, due both to lack of solid cover, or lack of bottlenecks to really clamp down on. Being able to blow away an entire front-line push with some well placed TNT could very well make the difference they could really use.