Enemy dominion too high for me?

[Saxon]

I would suggest you need your prophet involved in the preaching. Hopefully, you made a holy unit the prophet, so now you have higher holy skills than normal. This helps a lot in this sort of situation and also gives access to higher level spells in combat. Some people like to make an expensive unit the prophet to cut down on maintenance costs, but I prefer having that extra holy power.

The other advantage to having the prophet there is the free temple check they provide. I understand your reasons for keeping the pretender unit away from such horrible domininon, but a the cost of losing a prophet is usually quite a bit less.

The other, longer term, solution is temple spam. Build temples in your back provinces, so you get some extra push outwards. By the look of it, your enemy is pretty strong in this area, so you are going to have this problem for a while. Long term planning may help. That plan way well include how you are going to invade them without using your pretender. Very long term, I usually find that defeating someone with better dominion is usually done by taking all of his provinces. It is hard to turn around a dominion advantage, much harder than other areas. You may just have to live with it and hope he doesn't case Dark Skies.