I develop for MOS for fun and agree with you on many points... and on some points not.
What are there: - Scribble (not EMacs/IDE, but still a nice editor) - CVS (svn/git also have their problems... none of them are perfect!!)
What I really miss: - GDB - Memory protected environment - More complete documentation - More and better examples - Sleep could be also nice... It is easier to continue the work... (On a robust system).
What I NOT really need: - Virtual memory - CMake - QT (maybe for porting programs from Linux, but...) - Multiuser (why) - Package management (there is something, but I don't use it) - C++11 support (but a recent gcc should be released more frequently)
What the biggest problem is the fragile system (no memory protection). The programming feels like walking on thin ice... On Linux, the kernel protect (mostly) the system from my faults.