It is possible to make rottenburg into a CP map, but like I said you'll have to do a lot of work. I just checked out your update and wanted to point out a few things and make some suggestions.
First off, you're gonna want to block this massive sightline because a) it's ridiculously long and b) it's nearly impossible to counter.
Next, your hud icons cap in the wrong order. See this is the second point and it looks like i'm capping the third.
There's some funky vis issue happening here at the last point that I haven't any clue how to fix, but I'm sure some more experienced mapper can help you with that.
This flank, the route the tank sometimes takes, is lit very poorly and is way too long. You should either shorten it or remove it entirely.
Lastly, I know being able to go on the roofs is the Selling Point™ of your map, but it just doesn't work well. They're so steep that you can surf on them and from some rooftops you can see right outside the map. I honestly suggest replacing the clips.