Have you tried the latest KDE? It's very customisable and hasn't crashed or required manual restart for me once in the last 3 years, even when I leave it running for days.
I did try it again (after many years) just last month, unfortunately I find it hideous and cluttered, even after an hour or two of tweaking. You're right it should be the answer, but I felt deeply unhappy using it. (My problem I know).
Edit: It also has session-saving support.