There may be some magic pair of $200 hyper-gore-tex-blah-blah-blah waterproof gloves that solve this problem but A: Given my track record on gloves that don't work I'm not going to invest that kind of cash on another disappointing pair of gloves. And #2: I have a theoretical limit of about $50 on gloves because you need about 5 different kinds to cover all types of weather and temperature and (See A Above).
Enter the magic of finding roadside treasure. About 2 weeks ago I found not one but a full pair of PVC coated gloves.
I got to try them for the first time in the rain. The coated part is 100% waterproof and windproof. At 40F they were plenty warm in the rain but there is enough room in them for a liner to get down to freezing, and below that there is no water, so no waterproof glove needed. The open cuff design seems to significantly reduce hand overheating and sweating. The minimal sweat that does build up wicks nicely through the liner and dries quickly. Dexterity isn't great but manageable. The only downside is that the cuffs aren't waterproof but my jacket came down under the cuff and it's my fingers that usually freeze in the rain and that problem is solved.
Of course all of this is based on one 40 minute ride in light rain......but I think they will work.