I've played a lot*of Memoir '44. With its expansions, I'd say it's a deeper game than BattleLore is at present. BattleLore begins deeper when just comparing their basic sets, but the BattleLore expansions have mostly been profoundly disappointing whilst Memoir '44 has been getting better and better and better.
The Memoir '44 Campaign Book then takes the game to an entirely new level.
Days of Wonder seriously blundered with the expansions to
BattleLore: consider that a M44 expansion contains about 44 terrain tiles, 66 plastic miniatures, 8 scenarios and a few badges and tokens (about $33), whilst the bigger BL expansion (Hundred Years War) contains 0 terrain tiles, 32 plastic figures, a few rules summary cards, and only 5 scenarios (about $30)...
I'm sorry. I enjoy BattleLore quite a bit, but the expansions were absolutely pathetic compared to those of Memoir '44. (The M44 expansions also tended to give you a bunch of special rules to play around with: trains, mines, field bunkers, special units and more!)
I'm really hoping that with FFG now owning BattleLore that the expansions will improve their value markedly.
A recent game I had of Memoir '44 had the Russians trying to bring through a train with their reinforcements on it, whilst I had a plane pinning down their troops in another part of the battle... That was a fun game.

The basic M44 system is the simplest of the four systems, but the expansions make it far, far superior to BattleLore as it is at present.
Cheers!