SMP needs to be turned back on and debugged. It needs privileged instruction emulation. Some kernel memory protection needs to be added so it can be used as a secure jail.
Performance needs to be improved.
The tracing thread is a peformance bottleneck since every system call results in four context switches. Eliminating it would be very good for performance. The block device is currently another problem. It can only have one outstanding request at a time. As a result, the performance of IO-bound processes suffers.