What bothers me most is the fact that tabs aren't as useful as they should be - I want folders to always open in tabs, resulting in just ONE finder window unless I explicitly say otherwise. Instead whenever I trigger an action that shows something in finder I'm presented with a new window. In my typical use case I'll end up with several finder windows unless I manually merge them.

Finder tabs should behave like browser tabs, where opening in a new tab is the default action unless the user really wants a new window. Total Finder, a third party app, did this better.