Maybe it's a bad example image I posted.

The way you offered just creates connected (opt. seperated by br.wall, simple doors) and filled rooms.
This would become boring in the second level.
Furtheron there is the problem with doors & keys.
How to place them in a correct order (you have 4 colored keys/doors) and need the right key before you approach the ref. door.

The perfect generated level I think should be a maze with rooms (not vice versa) and a correct sequence of keys/doors.
Some rooms should have no door but just a br./move wall.