The La-7 has a wing loading of 38.8 lbs/ft^2. Compare that to the F4U-1D at 38.7 lbs/ft^2, the 109G-6 at 40.0 lbs^2 or the Spit16 at 35.1 lbs/ft^2. (All at "normal loaded weight")
The La-7 does not have small wings for its weight. You're just being fooled by the fat fuselage.