My g5 died like that back in 2009.
I also had a 2008 MBP that was much faster, so I didn't miss it much.
I agree, the base 1.4ghz/4gb/500gb HD Mini is not a suitable general purpose computer. I have one for an iTunes server - it just runs iTunes 24/7 with home sharing and a big media library on an external disk. It works just fine for that. But using it for anything else is really frustrating. It can take 30 seconds just to open an app like Safari for the first time. System preferences takes around 45 seconds to open. OTOH, a 2012 base mini is quite usable however, and can easily be upgraded to 8gb or 16gb. But I wouldn't want to buy one of those today.
Definitely worth the wait to see what Apple introduces this fall since we finally have a credible rumor of a new Mini. But if it's the $500 pricetage that attracts you to the Mini, you may be disappointed. The rumors have suggested a "pro-focussed" Mini that will be more expensive than the current entry level models. But of course, nobody really knows.