I would think it worthwhile to increase pagesize to 8KB. You have
low selectivity (many duplicates) with deep index structures - this
sounds (to me) to mean lower performance. How much "lower"? - I couldn't say.

If testing proves that the low-selectivity indexes are beneficial - keep them.

As for (missing) Primary Key: I try to (almost) alway have a (32/64
bit) Primary Key. There are exceptions, but I often regret those.


--
Aage J.
"Quidquid latine dictum sit altum videtur": approximate translation:
"Anything said in Latin sounds exalted".