There is no perfect solution to this problem. I fish right up till freeze up almost every year. If you use wool fingerless gloves they are wet in short order and if there is even a slight breeze can be worse than no gloves at all. If you use neoprene gloves that DON'T LEAK, you can stay dry but loose dexterity and they insulate about as well as a layer of sunscreen. I have tried a number of things and some work pretty well, but as in most things in life aren't perfect and have tradeoffs.
The one that has worked for me the best is a pair of neoprene gloves that are fairly thin and do not leak. Any leak they start to have, I fix right away with aquaseal and if needed a quick resew. As I had mentioned they do not stop the cold. So I put a pair of fingerless wool gloves over the top of that. Even when they are wet, they do keep you warmer. It is just because the water is not against you.
I also bring more than one pair of gloves. I have a pair of wool gloves that have dipped rubber palms and fingers. These are OK till it gets into the mid to lower 20's. I generally start off wearing them while it's still light and switch to the neoprene/wool combo after it gets dark and the temps really start to fall. I keep those inside my vest (sheep skin lined) so they are warm when I switch to them.
One more tip. When your hands start to get cold, stop and hold them in your clothes till they get warm because once they get really chilled the game is over. You won't be able to warm them back up till well after you are back inside with the heat going.
I know it is not as easy to cast and strip with a pair of gloves on, but letting your hands freeze is not really a wise option either. I used to work 10 hour days outside on a snowmobile in weather as cold as -40 F. Actually that's -40 C also. That's where they meet. But I digress. The key to staying warm is keep your hands and feet warm, and wear a good hat. Something like 90% of body heat is lost through the top of your head. (Can you ski naked if you wear a good hat?
) I also wear a lot of layers. A good jacket is pretty much not an option because it interferes worse than gloves do in casting. I just wear a lot of layers. If you look at a photo of the last day I got to fish last year you can see, no jacket. I wish the neopren/wool gloves were in the photo but I looked at every photo I have uploaded to anywhere. No picture of them. You can see the wool/rubber ones in the pocket of my waders though. I'm pretty sure I had swapped them out to the other gloves by the time this photo was taken.
If there is one key to staying warm it is not letting your hands and feet get cold. Once they get cold it's over.