Fire Weapons-Hades-Flamer-Carousel,
Hades-By far the most used in the game atm out of the three in my opinion, devastating at any range i think even without the fire damage it causes it would still be the most used, with the de-buff to guns you suggest this could be potentially be over powered close with say incendiary rounds making a close range Hades more viable and getting people to use incendary over say greased or lesmock, it would be fun to see also makes people going up against such a combo of say carousel hades pyra, use heatsink mixing up the tactics which is never a bad thing,
Flamer-i have been working with some new builds trying to break up the meta a little and an effective pyra build that i found was flamer carronade flamer side, up close this build is deadly because of the added flamer to the side and trifector parts/guns get broken and disabled quicker, if the stack decreased was in place i feel one flamer would be viable and then free's up that combo for say harpoon carronade flamer so they stay close >:-) *insert evil laugh here*,
Carousel-I think the carousel is underused even with the increased spread, on my junker i have a carousel flak side hades front, so a mid/close range build anything that does not have an artimus merc, is in for a bad time, i use it similar to hawatcha gattling goldfish just slight adjustments from front arc to the side then back, i personally would rather the carousel have an arming time put on to it and the spread decreased so we could have a mid range meta game to go with long and brawler, in my opinion that is my preferred style of play you need to watch for terrain cover and be deadly all while being close enough to see the foe charging you or bringing gun arcs upon you,
In short i agreed completely possible even go one further by adding the same mechanic to engines but maybe higher stacks, it would be a simple change that would break up level of play for a new refreshing time of raging that no one brought chem spray/heatsink