The introductionI'm a magic player with a lively interest in Vintage, but due to budgetary reasons I'm restricted to playing casual. During the creation of a casual UW Fishlike deck I decided to cut one plains for a Karakas I had, because Wastelands are non-existant over here and the card added some style. After testing a couple of matches I started to think some more about it and noticed some major advantages.
I'd like to say I have hardly any serious playing experience in Vintage, and most of this post will be purely theoratical. I'm not trying to tell everyone to play Karakas, but I do hope to make people think about this card and discuss it.
But first for those of you who don't know the card:

Errata'ed text:
Karakas
Legendary Land
T: Add W to your mana pool.
T: Return target legendary creature to its owner’s hand.
The pros:1) Uncounterable
2) Wrecks Oath's double angel team (pre-board)
3) Creates colored mana
4) Saves Kataki's, Isamaru's and other creatures
5) Many random advantages
The cons:1) Non-fetchable
2) Wasteable
3) Legendary
So what I'd like to ask: Has Karakas been tested in for example UW Fish? If so: why didn't it turn out valiable? If not: might it find a place?