The action buttons are always vertical, regardless of the panel's orentation. This means on a panel of 30 px height they are tiny and one can hardly click them.
Well that is somewhat on purpose, because if you want them in the same orientation as the panel you can also add 2 plugins ;-).
While I can follow your logic I doubt the users can. In the old panel the orientation could be configured, so from a user's POV it looks like a regression.
*** Bug 7226 has been marked as a duplicate of this bug. ***