All of your maps that I've seen have the same problem; they're INCREDIBLY basic in layout, with a boring, usually flat plane with a few props scattered about to give the illusion of design or detail.
Here are the problems with this:
1. It's very plain, and honestly boring. Without walls to hide behind, corridors to navigate, raised platforms and stairs to play/jump around on, it will be overpowered by Snipers. And also nobody will have fun.
2. Everything above. Your maps mostly consist of what can be summarized as single rooms. This is a fine thing as you're just starting out, but instead of uploading them to TF2maps, I feel personally that you should experiment with these kinds of maps if you're having fun, then when you feel up to it try making a 'proper' map (I.E. one that could be considered as playable in a server).
Trust me, it's a great thing to have discovered Hammer and suddenly realize that you can create your own worlds, but I don't recommend patching up your first doodles and packaging them as maps when they really don't feel like they had much effort behind them. They could be potentially useful if you want to start making gamemode maps instantly without setting up the logic, you could make a new map from all the logic that's there.
I would recommend looking up design theory documents on TF2 level design, you might get a sudden burst of inspiration. Or just play the game and see what makes a map fun, stuff you really like is stuff you can try incorporating into your levels.