What would you say is the problem for Brits?
I'm speaking strictly from a team games perspective. The firefly is really lacking compared to other TD options and doesn't perform well for its cost. As you've mentioned, its not mobile enough to respond to threats especially massed Panther pushes on a single lane. The slow turret rotation doesn't help its case either. I hate the tulip rocket gimmick and wish it could be balanced and replaced with a flat stat buff to make it more reliable vs gimmicky.
As I've mentioned in other threads. I really want to 'fix' how easy it is to get value with Panthers without actually nerfing them. There needs to be stronger counters to the Panther while the Panther retains its great AI and AT potential for its cost. A more mobile Firefly, I believe would be a great start.
First thing is first, IS needs to have snare. It was justified since they had way better AI than any other mainline infantry back then. But it's not anymore. It NEEDS TO HAVE
Give stock average mortar. Delete emplacement in return. I don't care.
IS can't get snare for some reason, buff on AEC is needed.
Rollback repair speed of heavy sapper. Churchill is not an option after it's pop can nerf & sapper's repair speed nerf.
Buff Churchill's pop cap. Buff on Comet in terms of AI would be nice(but not likely to happen)
I'd say FF is good enough if it gets it's turret rotation & mobility buff. And AFAIK, it is on the patch log of upcoming commander patch.
Don't get me wrong here. I used to play UKF since CoH1, and it was my main faction. I just don't play it anymore because it's not playable faction at current balance. Just look at the stat from coh2stat.com or ML5.