That has some similarities with my Cloudpost/NicFit hybrid, see here
http://www.mtgthesource.com/forums/s...=1#post1015935 . The maindeck is still the same, the sideboard is going through some minor changes.
Also, Brael tried Dark Depths in his earlier lists, but cut it and just kept the Crop Rotation package.
So, unless you want to try my actual list including the Cloudpost package (i like the list a lot, but it's of course different from your deck), one thing i would do at least:
You want to play Crop Rotation in this deck. Maybe not the full 4 copies like me, but at least 2. And you want Karakas and Bojuka Bog to get with that to deal with a couple otherwise problematic matchups. Knight can get those cards too, just Crop Rotation is faster and against combo decks you need all the speed you can get.
About results: I have still around 75% winrate on xmage after ~200 matches with this now. Depths plays a major role in my deck. Access to the combo has 3 big advantages:
1. Delver decks have not many answers to Marit Lage, if you can get the token into play they will usually lose. That allows me to get away with very few removal spells and still have a good Delver matchup (now i'm at 17-6 combined against different Delver decks - considering i'm playing Cloudposts, and Cloudpost decks are usually awful against Delver, i'm very happy with that).
2. Against combo decks, you have access to your own fast combo. That's rarely fast enough on its own (but it can happen), but it means you can often get away with just enough to disruption to stop their kill for 1 or 2 turns. My combo matchups are for the most part really good and almost certainly better than for other NicFit decks - that has other reasons too (Mox Diamonds, maindeck Gaddock Teeg), but without Marit Lage it would definitely be worse.
3. Against some BGx midrange decks, you have access to an "i win"-button - that way i have stolen lots of games i could never win with a fair game plan.
Notably, the combo is pretty bad against fair decks with white mana, especially Death&Taxes, so in those matchups you should board out the Depths and probably have a good alternative plan (for me, that plan involves Cloudposts, because those are the matchups where that plan is usually at its best).
With your deck, you will probably be a big favourite against Delver anyway, but the impact against combo decks is very relevant and the ability to steal hopeless games against other midrange decks is always relevant.