My latest GW-60 watch has developed a charging problem within a month or two after I got it to replace one where the screen broke when I dropped it. One of our GPSTC members had also reported problems with battery life, but he used the watch for ice surfing, so temperature might have been an issue.

Has anyone else had problems with the GW-60 suddenly not charging anymore? If so, are there any tricks to fix the issue?

The computer connection is no problem. I can download data and update the firmware. I tried going back to an older version, but it did not help.
The first time I noticed the problem, the watch seemed to charge fine (screen was lit, battery icon was flashing). I let it charge over night (which so far always has worked fine), but it was still in the same state the next morning. At some point, the time reset, which happens when the battery is completely empty. I eventually hooked it up through a USB tester to see how much current was flowing. Most of the time, the actual current is 0.00 A, even when the battery icon on the watch indicates that it's charging. On my other GW-60, I get charging currents of 0.09 A with a half-empty battery, using the same cable and USB port.

Sounds about right. Warranty instructions in the manual (and Locosys) say "contact the dealer". Then, dealer contacts Locosys (right away). A couple of days later, Locosys contacts dealer with questions and a request for pictures or videos.
It's been 5 days so far, and I still do not have instructions on where to send the unit (Locosys directly or dealer?). The dealer has been quick to respond or forward every single time, and I have answered emails within a few hours.
I've had a few GT-31s that usually lasted many years. Of the three GW-60s I bought within the last 9 months, two are broken. One was my fault because I dropped the watch onto pavement, but the drop (less than 1 m) would not have broken a GT-31 or even a GW-52. I could not get a price estimate for the repair from Locosys - "contact your dealer". He suggested that buying a new watch (at a discount) would be cheaper than shipping the watch four times (to him, to Locosys, from Locosys, then back to me) after paying for the repair, too.

Two other guys on our team had different problems with their GW-60s (tons of artifacts in one case, and low battery life in low temps in the other).

All that has been somewhat frustrating. I wish there was a viable alternative to the GW-60 available.

I had a feeling locosys would come good, that's encouraging news. Lets hope yours is indeed an isolated case.