I just hope the reward is good. Azura's ring svcked. The Dragon armor in OB was really good in terms of DP, but the enchantments weren't good. I think armor and weapons don't make good rewards even though there cool because there's a chance you aren't skilled in that item. Something everyone can use would be the best.
While Azura's Ring wasn't very good, I also consider Sunder, Keening and Wriathguard to be rewards for the main quest since you inevitably got them while doing the main quest and could keep them once you finished. Some of the main quest dungeons also had some nice loot, though I wouldn't say that counts since they're not actually part of the quest, and you could potentially miss them.
But I kind of agree that if the main quest reward is equipment, there's a chance you won't have a use for it, though that might be adressed by giving the player a choice of what you want. Let's say the game ends and someone offers to forge a suit of unique armor for you, you could then choose between light armor, medium armor, or maybe you could also choose an enchanted robe if you lean towards clthing, that way, you could choose something more suited to your needs.
Alternately, you can give players something that anyone is likely to be able to benefit from, a fortress seems like a good option, it seems reasonable to me, when I just risked my life to save the world, I think I deserve something impressive.