Learning to hack around the limitations of a tiny machine is a good step toward becoming a seasoned software (and possibly hardware) engineer!
The advantage of tiny systems is that you can understand them completely, from silicon to OS to software.
The 6809 is simpler than the 68K, and more powerful and orthogonal than the 6502, but there isn't the same software base for it. I think Motorola was onto something with the 6809 and 68K instruction sets and programmer-facing architecture. IIRC PDP-11/VAX and NS32K are similarly orthogonal.