The problems are these:
For the same reason you want to do this IC, these realms have their own histories, and don't want to split up. If you really feel like small realms, create it in Lukon. You could easily arrange a schism of the state in methods of fracturing from an undesirable government, or rewarding your dukes by granting them independence. From there you can either fight amongst yourselves or war others.
In general, Oritolon seems to keep to itself, and political turmoil will eventually split it up.
OT isn't exactly known for its military prowess. A war between them and MT and the Guild could drag out nicely.
Secondly, I don't think many like the idea of an empire started by Lukon. Even if it didn't feel like surrender, people just don't like Lukon. They generally keep peace with them for their well being, but Lukon has been part of the destruction of every fallen realm in the Colonies, and in the loss of two of the realms capitals. As fun as Lukon can be some times, they just don't have any fans out there; they even turned on their allies from forever ago.
