The problem with this deck is that it can't really maintain control, or any real form of pressure against type 1 decks.
That has been an enormous problem for me when i playtested it. The original variant used 4 cunning wishes, and 4 burning wishes so it was much easier to wish for control cards. However, tutors may be a better solution for the lack of wishes in the deck. The control elements themselves need some work, as they depend so much on domain being out. Dual lands are a better option (see third quote below). It is fun to see most players pissed off when they only have one land, especially when they run all mono-colour decks, but usually a global ruin comes out too late to win me the game.
Of course, if this is merely casual, then go right ahead with this idea...
The thing is, I'm trying to make it more competitive (hopefully without having to add power), a sol ring might be of use in this build. Post any ideas you have, I know there are other domain players out there! :P
Are you aware that dual lands count for domain?
Yes, I am aware, but they're also targets for nonbasic removal. And also incredibly expensive in enough multiples to play in this deck. But I like the idea, and I'll probably incorporate them into the deck. Although its difficult to decide which ones I should play... should i play 4-ofs of 3 or 4 dual lands, or lets say 1 of each of the ten dual lands and then fetch for certain ones i need?
EDIT: Do dual lands actually work with harrow, or are they only basic lands while in play?