You've probably picked up on this already, but if you just reverse prop direction and see immediate improvement, then it means your plane was out of trim, but doesn't necessarily mean you've found the better prop rotation direction.
If you're flying at a level high enough that prop rotation makes a difference, then you need to re-trim the airplane to the new prop rotation, so if you take a super-well trimmed plane and reverse the prop, the first thing it'll do is disappoint you.