Random Generator gave me Manaforce Mace and Island. Island color shifts the mace to blue... which is kind of odd, but okay, I'll do that. The Mace seems natural in blue, but, as per usual, I can't leave well enough alone, so it will get +1/+1 if you control a Locus or a Lair. There isn't enough land types in Magic for me to really worry about this, but it's nice to dream of a future where this would be broken.

I think I prefer it this way. Just having +1/+1 domain doesn't feel very blue to me, more white or green (Wayfaring Giant, Matca Rioters).

I don't know. I dig the idea that blue likes options. I think Green has been saddled with Domain concepts because it can easily achieve it. But if I was to list the two colors that are least likely to accept that their philosphy may not always be the best way to do things, I would say White, then Green would be the two most closed minded colors. On the other hand, while blue thinks its way is best, if another colors view point is proven to be more effective, I could see blue act like a good scientist and say "I don't know what red is doing right, but it is achieving results and I have to respect the data."