Actually, being behind on general skill level will not reduce the benefit of recon. If both sides are commanded by stupid level 1 generals with no traits, then yes, recon will not have much of an effect, because so many tactics are locked. However, if the scenario was instead, say, a level 4 general with trickster versus a level 8 general with every trait in the game, then the level 4 general will actually benefit a lot from having the recon advantage.
If the level 8 gen. has the recon advantage instead, then they will probably counter more than half of the tactic rolls, resulting in around 10% bonus to attack. However, if the level 4 general has the recon advantage, then the playing field is more level. Of course the level 8 general still has better tactics, but they will be less likely to counter the level 4 general's tactics. Think of recon as mitigating the effects of fighting against a far superior commander.
Light tank recon doesn't dilute armor/piercing (much). But I still wouldn't research recon past the second tier, and I would only research the second after all the important 1940/1941 techs are done.