Some Considerations

No-interrupts systems are very simple to debug
We already have a time base without interrupts
If the uC allows: see the AVR port
Don't underestimate the joy of lockless code

Single-interrupt systems allow precise data collection
You don't need to care much about printf/USB latencies
Still, the overhead of irq enter/exit can be high

The scheduler can introduce substantial overhead
A few microseconds or more

Device interrupts can destroy your well-determined WCET

When you introduce priorities, you face all kinds of problems
Deadlocks
Priority inversion
Stale tasks
...