Well, the real problem I have is that it is superior in performance to all of our 'prop' perk planes except the Tempest. I'd rate it equal to the Tempest in performance at low altitudes (which is, rather unsurprisingly, where the fighting is).
If you are in a Spit 14, an F4U4, or God forbid a Ta-152, you can't hurt an La-7 unless he screws up. He can joust, make a pass, extend out 3,000 yards and turn around for another joust. You can't just say, "Aw screw this" and leave... because the La-7 is faster. The F4U-4 can get away from a La-7 (if it starts with a big enough head start to run the La-7 out of WEP), the other two don't have a chance. Most La-7 pilots aren't stupid. They realize they aren't very good at fighting, or they'd be in a plane that can fight. So they do jousts, or camp out above and behind you and wait for 4 or 5 friends to engage before they'll take off their dress and get dirty with the rest of the kids. So your choice, if you choose to fly a perk plane (and even the Tempest) is to fly at 30k where you don't have to worry about La-7s diving on you with a 1-2k alt advantage (which is all they need to run down any prop plane) and forcing you to turn back into the conga line chasing you, or ... to just fly an La-7.
I actually don't care if the La-7 gets perked. There are other planes that would perform the same function for the inept pilots that make up the bulk of the La-7 population. The Typhoon comes to mind, and some of them might even go to the P-51D. What I would like to see is the perk costs eliminated or drastically reduced for our 'prop' perk planes. That would also have the function of adding 'diversity', since people WOULD fly the F4U-4 and Spit 14.