Even the smallest of level editors are going to be a complex beasts. That's basically the reason why tools such as Tiled exist, so the developers can turn their focus away from creating a tool that's going to drain resources and put them towards other aspects of the game. This much can be said for character editors as well ( anything from creating character atlases to creating a bone rigged character), these tools take up a great portion of the game, and large companies have dedicated individuals who work on these tools day in and day out.
Long story short, if your not willing to use pre built software, either purchased or freeware, be prepared to put the hours in to make an editor that's up to your standards.