I like the 6800. Two accumulators and a 16 bit index register is a good alternative. Totally understand your preference. The 6805 seems too cut down.

I have not written much 6800 code, but have read a fair bit. Had it been more available to me, I would definitely enjoyed it

The 6809 is the Cadillac of 8 bitters. That is what makes it fun. One can pack a ton of features into small spaces and doing reentrant, relocatable code is very well supported.

Stack abuse gets one a really fast memory to memory move too.