One major thing that is really freakin disturbing!
If you get overbid on ah, you cant bid again unless you have the full amout.
If you bid 100 and someone bid 101, you need to have 102 gold on you just to overbid with 1 gold so the bid is 103. Either you should get the full amout returned if you get overbid, or make it possible to overbid without needing insane amout just to overbid
Maybe its best to return your bids when someone overbid you to prevent people from using auctions as a "temp bank" for massive gold amouts
You only have to increase your last bid? so if i bid 100 gold and get outbid by 106 gold if i pay an extra 10 gold will push my current bid to 110 gold.