If so, keep it for a while, and just buy the 10 mm. The focuser restricts the field of view, but there are lots more eyepieces to choose from at 1.25-inch diameter than at 0.965. You can then go for a 10 or 12 mm Orthoscopic or Plossl, and a 40 mm Plossl or Kellner. If the hybrid diagonal does not work for you, you will have to hunt down eyepieces with 0.965-inch barrels in appropriate focal lengths. 10 or 12 mm should be no problem, but you will be lucky to find a decent eyepiece of that barrel diameter with a focal length over 30 mm.
Some folks think high magnification is what telescopes are all about, but there is a lot more to it.
If an object is sufficiently bright to begin with, then increasing magnification up to certain a point will generally allow you to see more details. There is no single answer. If you increase the magnification of your telescope in small increments, there are several reasons why you might want to stop after a while. And if you are patient and persistent, you may wish to try a high magnification even in poor seeing, in the hope that things may settle down for a second or so every now and then, so you can get a good look. Not only must the atmosphere be steady, but so also must be the mounting of your telescope, if the images are not to look wiggly.