I'd leave it alone. Of course, I'm a firm believer in "if it ain't broke, don't fix it".

To make it a bit more accessible, you could replace the screws in the back with thumbscrews like these
HERE. This will save you from having to use a screw driver to remove the current screws that you have to hold your side panel on (these scew on/off by hand).
If you were to get a new case, you'd have to transfer all the parts from one case to another, risking damaging parts (could get expensive, or might not happen at all). Also, as with some dell's and HP's, while a case looks like a standard ATX case, it might not be. The holes might be a half inch off in one place or another, or the motherboard used might have mounting holes in different locations that would require a certain case. Check into this to make sure that your case is a standard ATX case and that you can remove the parts and install them into another case with no fitting problems at all.
Best of luck!