I like the idea a lot, well done. My only concern is the items we will be voting for. I know that what we have seen in this test is just that, a test. But from the last vote we were given no choice on which items made it to the final vote. We seem to get left with 1 or 2 good items (one of which were only allowed to be bought once) then we had to decide which items were the next best thing from a pretty bad bunch.
Allow more items to be voted on and more items to be in the guild market. Then on the next vote we could vote on what stays and what gets replaced. I would hate to see a good item getting automatically swapped out. Also, decrease the prices just a little Who in their right mind would pay 1,250 guild coins for a black Knights adventure when they can be bought for 295 map frags or from TO for a few gold coins.
To sum up:-
More (better) items to vote on
More items in the guild shop
Decreased prices