The wishing well is a good thing, that I think everyone would build. But I think it has some flaws that should be addressed.
One, a notification. This is mentioned in another thread by another player but I'll just repeat it as I agree with it. It should have a notification, just as the guild has if there are unfinished quests. This reminds the player that the wishing well is still available. I almost did not do it the other day and I heard people have forgotten to do it. It is a potential 125 gems lost (if the player is extremely lucky).
Two, the wishing button. It is a thin, long button in the middle of a large panel. If I am the designer and there is something like that, I would make the button really big as it is it's sole purpose. I play on an ipad and I still think it's small. Its not a big deal but something to think about in the context of user interface design.
If there is anything else, feel free to add in the posts below. =)