That's a good question.
Personally, I would rate a game like Panzer Corps or any game related to Panzer General as "beer and pretzels to basic".
Complexity also often comes from the amount of units/the number of actions you have to take and not necessarily from how complex a game is to play. At its core, the actual actions in a game like WitE are often not all that much more complex than those in other games, but as you have to take them more often and with more units, the complexity increases.
I would rate Unity of Command as basic, intermediate due to the logistics and the quality of the AI in scenarios where the defenders have a realistic chance to slow you down significantly or stop you. It doesn't have the magical "more or less no matter where you are on the map, you can always resupply" excuse for a logistics system that Panzer General-like titles have, but it has a basic but clever supply system. The AI will also offer a challenge through what it does, instead of by just placing a wall of the cheapest unit type between you and the objective like in Panzer General and related games (including Panzer Corps).
It's not a really complex wargame, but if you want to win you have quite a bit more thinking to do than in "entry level" basic wargames.
WitE Alpha tester
Panzer Corps Beta tester
Unity of Command scenario designer