Rampage (especially charged), Spitfire, and even more so Devotion are in my opinion high-risk high-reward weapons as while shooting them you are just standing target.
Start missing your shots and you are dead, the enemy team is fast/smart enough to focus you - dead.
They don't see you or it is closer range 1v1 - they are probably dead.
In my opinion crazy slow or more precisely pretty much non-existing movement is well balanced by the strength of those guns. E.g. today missed my shots and a dude killed me with Flatline via what seemed hipire judging his movement speed.
I still think that Rampage should be if nerfed then only in close-range recoil - could be like long-range lmg.
Spitfire stays the same best of both worlds.
Devo stays the same reliable in longer-range pokes, monster close range with turbo.
p.s. just had so much fun while turbo was in a crafter, pity others realized that as well at some point and it was Havocs and Devos all over the place, I think I was the only one seldomly running Rampage still 🙂