Without any additional buffs?
You'd end up with extremely gimped faction until H or A is unlocked as brits would not have any staying power or any meaningful ranged damage.
Like I said, it would obviously require "slight" tweaking of stats and I'm pretty sure such revamps this late in the games life cycle are unlikely. Just theoretical what if -scenarios.
Now back to the What if part: I don't think basic mechanics like snares or flamethrowers should be put behind a doctrine or another gimmick like the aec sidetech so might as well give brits the same basic tools other factions have like the non-doctrinal snares.
Having increased utility and maybe some other perks it would be reasonable to tone down the raw firepower of the sections.
For example the USF AA halftrack had its raw firepower nerfed but it is still good because it has such great utility imo. It acts as probably the best mobile suppression platform while having good anti air and will scare off or outright destroy axis light vehicles and in the lategame can cover your flanks from infantry pushes. One can't headbutt a Panzer 2 with it (except sometimes when you can if you kite it) but the utility it has for the price of 310/50 it's a real bargain to get.
Also I think it's bad for the diversity of the game if some units just have more outright firepower without any other abilities. Although Red Alert 3 had its issues probably one of the coolest things in it was that every unit had a 2nd function. With proper micro and actual combined arms you could take down Soviet tanks with superior raw firepower with your weaker Allied tanks if you shrunk or froze them with cryocopters or captured them with a spy or used an EMP strike from a carrier for example.
I feel that I need very few combined arms after the December patch especially as USF in the lategame, all late game AT is handled by Jacksons and skillplanes while double BARred rifles will handle most of the anti-infantry and if need be M8 spam will support them. There is no point in me diversifying my build when more Jacksons and M8s have the raw firepower to slug it out with anything when properly used. I think this is the same problem people had with the Panthers in teamgames last patch because there was most of the time no need to build anything but Panthers when lategame kicked in.