you'd look for the same things in a semi or full hollow that you would a solid body electric. do you like how it plays? is its voice agreeable to what you think a particular guitar should sound like? is the fit and finish up to par? will the guitar be able to hold tune?
to play the devil's advocate to a small degree an explorer's specs on paper (minus the pickups if it comes with the ceramic mag humbuckers) would lead to it being a potentially great jazz guitar as far as solid bodied electrics go. a simple string change and a possible pickup swap will get you a lot closer to sounding more "authentic" AND you know your explorer's quirks and don't have to adjust to a new instrument. If I were in a similar position this would be the route I'd probably take as being in school would mean any money would be at a high premium and spending it on something I wouldn't technically need would be an ill advised idea
if you're still going with the semi hollow route I'll chip in a good word for the prs SE line and the hagstrom line as well. if you could get an agile AS series somehow then that would be an option as well (you would need to get the funds first and then sell the explorer which might make this option a no go) as I haven't heard one I don't like and agile does make some great guitars besides their ERG lineup
Contributing writer for guitars canada: www.guitarscanada.com
Guitar lessons for the Hamilton region in southern ontario in the comfort of your home, contact me via PM or the following email address: email@example.com