I beg to differ with the general direction of this thread; let me explain why.
Way back when Ringside first introduced their 12oz bag gloves I bought a pair and they were the best gloves I've ever used. You could make a good tight fist in them and the long wrist cuff gave added support to the wrist. When I wore them out I bought another pair of the same and they were slightly different but still good gloves. Recently I bought a third pair (this being 2 years ago,now) and they are crap. The new and improved attached thumb makes it impossibleto make a fist or to throw a punch properly. Given the odd angles dictated by the claw instead of a fist in the glove, wrist problems became inevitable so I threw them out. At the gym where I worked at the time I experimented with a variety of gloves, tendingtowards the 12oz and above thinking to protect my now sore hands.
I ended up with a pair of Everlast bag gloves, straight off the shelf and I love them because I can make a fist. That is the most vitalthing in keeping your hands sound: make a tight fist. Keeping your wrist straight is technique and strength of wrist and forearm. Do the approriate exercises.
How you wrap your hands matters more than the glove, I think. You want to be sure and do two things with the wrap: support and strengthen the wrist and keep tight the myriad small bones in the hand. Wrapping too much around and across the face of the fist-padding the knuckles- is counterproductive as the more times you cross the palm the less tight a fist you can make. The padding is in the glove and that won't do much good if your hand is only loosely clenched. The wrist band of the glove is no substitute for a good wrap and good technique. Make a tight fist and do the work to stengthen wrist and forearm and you don't need bag gloves; loose hands and wists and the gloves don't matter.