you just arent a happy camper are you..i think ive only seen you say two or three positive things in the entire skyrim general discussion..
to the OP.. it could be a great idea..but there could be some massive problems with it like getting to much gold. if they som how fixed that then ya lets do it.. also i would want to be able to fill the inventory of the armor and weapon shop myself. In OB i had so much usless armor and weapons in the chests in my house and there was no sense in seling it because i had over 200000 gold.
That sort of thing is inevitable towards the middle/latter part of the game. I sort of laid out a way so by owning the shop you can sell your goods at a higher percentage of their worth (thus an incentive to own it) but you'd have to wait a week or two for the inventory to clear. You could keep yourself from getting too much gold by upping the wages paid to your shopkeep. If you do the math right (which i don't really feel like doing haha) you could have a store that maybe nets you 10-20% more than selling to random merchants, which obviously isn't going to unbalance your game too much (especially with the wait time), but you'd have a cool weapon shop, a couple of fun side quests and a bit more immersion into the game world.
If you're the type of person that doesn't want to repeatedly revisit the store to stock your loot as merchandise you could easily have a sidequest to hire a smith to make iron weapons and armor. The gold you'd receive would be minimum at best but you'd still have the store.