I don't deny that having UP mainline infantry is a problem, but I don't think it's as bad as having OP mainline infantry. If 1/5 of the factions is 'non-viable', then its simply not played - the other 4/5 continue as normal. If 1/5 of the factions is 'wildly OP', it makes playing 2-3/5 factions incredibly frustrating (or impossible).
Also, I don't think the issue is the RA change (0.9 -> 0.85 out of cover); it works out to something like a 5.9% buff to 'eHP'. The problem is the moving accuracy change (0.35 -> 0.5), which gives IS' 42.8% more DPS when moving - that's what makes them similar to JLI.
/edit
I think a major source of the problem (regarding IS balance) is the massive number of 'states' IS can exist in:
Bolstered?
In Cover?
Weapon upgrades? (LMG, Piat, etc.)
Pyro upgrade? (LOS, Arty, smoke)
Medic upgrade?
Vet level?
Vet 1 and in cover? (more LOS)
Grenades unlocked?
That's just non-doc IS when in combat, without having to deal with auras and abilities. That's an incredible number of combinations to balance. Compared to Grens:
LMG?
Vet level?
Rifle-nade unlocked?
I'm pretty sure CoHronacup shattered this "wildly OP Brits" ruining all balance argument with the pick and winrates so lets stop repeating it shall we. They went 0-2 in the finals and axis didn't exactly struggle even in the games Brits won in build up rounds (pfc vs kimbo for a prime example).
A 42.8% increase is irrelevant without context backing those numbers up. What's important is how that final buffed moving acc or moving DPS compares to other mainline units. Ok so Tommy have 0.5 moving acc.
Riflemen have 0.6 moving accuracy (this is even without BARS), are they similar to JLI? Why is there no crusade for rifleman for breaking the balance between five factions. We also have fiveman grens that are slightly stronger than bolstered Tommy, yet we had no threads calling for a hotfix to grens.
As for the factors in balancing Tommies vs gren, Ost have similar capabilities it's just more spread around eg pios (similar LoS to cover section). Pgrens (AT infantry), grens (medkits and med bunker). Also PIAT Tommy is hardly a balance issue lol
I'm not saying Tommy are perfect and require zero changes, but this patch has put them in their most balanced place yet.
Balance team should be applauded for that.