I think the biggest problem is the board is too big.  Reduce from 10 ranks to 8.  And you can also solve the problem of KR vs K not being won on this board by adoption the Launch Square rule used in Brouhaha and Apothecary - the hanging corner squares disappear as soon as they are vacated.

A possible mutator variant of Omega Chess would be to simply use the same basic 10x10 setup of Omega Chess, except eliminate the additional 4 edge corner squares and the wizard pieces from the picture (such a mutator variant might be called 'Decimal WAD Chess'). This would, for instance (as in standard chess), allow K+R to always mate lone K, and incidentally allow K+Champion[also known as WAD piece type] to force mate vs. lone K on such a 10x10 board too (the latter Dr. Muller has related elsewhere). One price of this would be that unlike for Omega Chess, 2 knights+K could not force mate vs. lone K (as also is the case in standard chess).

Interesting extra pieces and pawn movement rules here.

The possibility to black out squares already existed in the interactive diagram, although it was not widely advertized: when you define a piece named 'hole' it will black out the square wherever you place it. No piece can move to or slide over such a blacked-out square, nor can such squares be grabbed and moved. The Design Wizard currently does not provide a means to create holes; you would have to add the required line by typing it in the HTML code, like hole::::e4,e5,d4,d5 to blackout the board center of an 8x8 board.

The main problem here was to get the unorthodox e.p. capture right. The XBetza notation uses 'e' as modality to indicate e.p. capture, and this can be used as alternative or in addition to 'c' or 'm'. Its meaning is to capture the last-moved piece on an empty square it passed over. The diagram uses the convention that this can happen on each square where an initial-only non-jumping move (i.e. containing 'in') could have been blocked, but originally the 'n' modifier was implemented only on D or A atoms, testing only one square. This was fine for FIDE Pawns, but in Omega Chess we must deal with an ifmnH as well. The diagram code for handling 'n' has now been beefed up to test two squares for blocking, and test up to two e.p. squares for strictly forward pushes.

Castling

As for the castling with a non-corner piece: the diagram uses an algorithm that always allows castling with a piece that moves like an orthodox Rook, even if it is not a corner piece. Official XBetza notation for this would be isjO2, the 'j' on an O (= castling) atom having the specialmeaning that you 'jump' a square when looking for the castling partner, starting from the edge (or at least the nearest blacked-out square). The diagram description doesn't even need that, but of course would fail if there is a non-corner Rook on the King rank that you don't want to participate in castling.

Omega Chess has 2 interesting new pieces that fit together well tactically
with the original pieces as well as each other. That is its strong point.

The Champion turns out to be the much stronger piece compared to the Wizard
which loses value as the game goes on. The Champion turns out to be one of
the strongest pieces at the end of the game, but its a bit dull to use at
the start like the knight which needs an extra move to attack.

While the 10x10 board makes the Wizard an interesting piece to use, Omega
Chess also suffers from not having enough tension between pawns and
fighting for control of squares as compared to variants that maintain the
same distance between the pawns.

Having more space between the pawns (2 rows) leads to more complex
situations, but having that much space also makes the game a little boring
when pieces are just setting up with apparently no reason for doing so.

If pawns are the soul of chess as Philidor said, then Omega Chess pawns are
not at the soul of the game. The pawns simply don't push away key pieces
often enough creating a space advantage for one player who is moving its
pieces in the right order. So while extra space may seem like a good idea,
it hurts the tactical considerations of pawn move that normal Chess has.

I believe Omega Chess is a step in the right direction in terms of the
evolution of Chess, but its unlikely that a game without enough tension
between pawns and a fight for control of the center will gain that much
popularity among the general population.

The fact that certain options rules in Omega Chess Advanced like temporal
knight have been suggested which gives the knight more range suggests that
the original setup of the pieces is not quite ideal.

The knight and the champion just aren't exciting enough soon enough. With
rooks, bishops, and the queen becoming even more powerful, the short range
jumping pieces need to be in better positions to create more interesting
interaction between sliding and jumping pieces. The wizard is also a little
far away from the action. Even after moving to its general development
square, it still doesn't seem to be that much closer to doing something
interesting except along the right or left flank.

I thought the definition of 'major' was 'able to FORCE checkmate with only the aid of a King'?

If your standard is 'able to deliver a checkmate if the enemy King cooperates', I believe the Rook also qualifies (can checkmate enemy King near the center of an edge if friendly King has opposition).

But I can't for the life of me think of any reason that would matter.  The force mate definition tells you the minimum amount of material you need to preserve to win a simplified endgame.  How does knowing that a Bishop could hypothetically deliver a checkmate *if your opponent decides to help you* have any effect on gameplay, let alone piece values?

This game adds in an ingenious way the movements of several pieces of
Tamerlane chess, which is the 'grandfather' variant of all these XX and
XXI century 'chess variants boom': We have the camels, dabbaba, ferz,
alfil and wazir.

What if they were mixed on the other form? Substitute wazir by ferz (so
the champion is now colorbound) and the ferz by wazir (so now the wizard
is not colorbound). Anyone can try this at home without breaking
copyright. I think... But my idea is not that. Just to say that is is
interesting to try to see if the game becomes more complex or not, more
interesting or not.

http://www.omegachess.com/home.html?action=advanced#undefined

Omega Chess Advanced has added a new piece:Fool.

The Fool assumes the identity of the last piece your opponent has moved.

Here is a board that could be a very good solution for making the Citadel
chess and Omega chess corner squares more playable:

http://www.alessiominiatures.com/Quickstart/ImageLib/citadel.jpg

Interesting ah? : )

Ohh, I'm eager to see your entry!  I think that having the Grand Chess
army plus Omega Chess's extra leapers on a 10x10 would be a good amount
of material and an interesting piece balance for an exciting game that's
not too long.  Omega Chess just goes on too long without enough tension
...

I just got my board and I will give Omega Chess an excellent for several
reasons.

   It is a great game!  The two new pieces make the game more enjoyable
and it is fun to use the pieces when attacking or defending.
   The pieces are high quality staunton design pieces and they will last a
long time.
  After playing with my friends they got interested.   It is a fun game to
play with almost anyone.

 I think that almost everyone will be happy that they got an Omega Chess
set.  I just love my set!

I haven't played this enough to know if there are any 'cheap'
unavoidable openings, but it seems for now to be a great game. Don't
leave your orthochess training comepltely at the door, because alot of the
same principles apply here. The only odd thing I find about this variant
is castling. You need a consolidating move when castling kingside, and 2
when castling queenside. For that reason, I don't see anyone adopting the
queenside castle.

If you order a set from the company, then know that these sets are really
good! The old pieces look & feel almost like my standard USCF plastic
pieces. The new pieces are just as good, and that cresent moon on the
wizard is NOT going to break off or bend without a hammer. The board is
top quality too as far as 4 fold carboard boards go. I'd prefer a vinal
roll-up type board, but that's just personal preference.