Yes, it is really practical to make a game specific editor for your own taste and requirements, but it is quite a big work. I know because I'm also developing my own
I decided to choose this way because I need special map decomposition for RTS pathfinding and AI, and because there is no other editor I could use for very fast outdoor level design.
I have little practice in effects, particles, shaders etc., so an editor that gives a complex flexible help for graphic design by a nice gui would be really fine...