Wouldn't it make sense to remove the Blast/Flame armour since those don't actually hurt your opponent as well?
The armors give you the ability to take on more enemies at the same time (or counter a special weapon). They provide very strong wide scale defensive abilities. Someone with blast armor can take an entire team on at the same time and win.
The foam however impends the player. Reducing movement, vision, etc. To spray yourself would just turn you into a sitting duck. If you need flame proofing that is what flame armor is for.
A special weapon needs to give a player a distinct advantage, immobilizing a player is just not enough.
This would be a really fun weapon for sure, but to get made it needs to evolve to provide a distinct advantage.