Agreed! Even if there aren't different levels available, at the very least you will have more ice time. When I was in California for work in the summer/fall, I took an adult group class that shared ice (and sometimes a coach) with the adult freestyle group, and I really was challenged to work on skills in sequence. Not to mention that the coach was a nationals level ice dancer - so all sorts of turns and sequences and basic corrections that helped so much!!
Anyway, my class at home is not divided into levels, but I appreciate having the time to work on different skills. I agree that working on basics always helps, and the two big things I've focused on is staying square (always!) and not looking at the ice. Thinking about knee bend and just being able to go over elements I may not otherwise practice often is good too
Oh, and I suppose you can always do skills other than what the coach tells you! There is an older woman in my class who frequently practices her spinning if she gets tired of edges, crossovers or whatever it is we're working on. Coach doesn't mind at all! Plus, she often gives students harder variations to work on anyway!