There's some truth in what n0 says. The game is almost ten years old, and partly as a consequence of that fairly limited in how customizable it is. I have had numerous ideas myself which would have required the game to support júst that little feature it didn't support.

As for there always being something wrong, well, that happens to everyone. There's almost always something better than what you have done. Something revolutionary, such as say an Agama tileset or RHG, isn't made everyday, which should be no reason to be discouraged. Several of your uploads scored higher than 7, I wouldn't say nobody liked your levels then. Heck, recently I had a lot of fun playing a few games of CTF in a level of yours.

I think what you should do is go create levels for yourself, rather than for high ratings. You can never please everyone, but you can please yourself.