1. First, the Lee Enfield in PR is already borrowed from FH2. Second, the model was never made to be used with 3d Ironsights, so there are some problems when PR uses it as such. Third, the FH2 developers prefer the 2d+3d combo they have now, so it's unlikely they will change it.
2. It's only on early war maps that Brit tanks have a disadvantage (namely, being armed with 2 pounder guns, which have trouble penetrating their German counterparts at that time period). Once the Brits get more tanks armed with bigger guns (Crusader MK 3 w/ 6 pounder, Shermans and Grants with 75 mm), it becomes more even. They get Grants first (around the time of Gazala), then they get Crusader 3's and Shermans at about the same time (around El Alamein).
3. The BF2 engine has problems with large, moving warships. Namely, anything (vehicles, i.e planes on a carrier, or infantry moving around on deck) on it will suffer damage and eventually die/explode. There have been some breakthroughs, but FH2 hasn't yet moved to a theater (Pacific) nor made any specifics maps (battles in the North Atlantic) where they need boats. That said, there is a (mostly) working submarine made by the FH2 Devs in the game files, it's just not used on any stock maps (yet).