In a way there are. Stopping a barrage make the gun cooldown faster than letting finish the barrage.
True but also not really worthwhile, since it cools down sooner rather than cycling faster. right now for the LEFH for example, it has 70 seconds of reload -> 9 or 10 shells for a firing time of 30sec approx; maybe a change to 4 shells fired over 12 seconds -> reload 30-35 seconds, approaching pack-howi barrage timing, could work.
I could imagine it being competitive in 1v1 against regular rocket arty, possibly, against double AT gun build, since smaller reloads mean you can keep chasing them around with barrages.
it would also make long random barrages that pick off squads in a huge area over a very long time in teamgames less prevalent, which is annoying to fight because you can't really do anything about it except hope to be lucky.