I find that with earth boots and summon earthpower I can still get blade wind out of the IF black priests.
I don't usually make my black priests 2 E, 2 of their random pick. I usually only give additional earth power to the priests I'm using for blade wind. Now, I do take really good care of my priests that end up with earth as a random pick. Because they are really, really good at blade wind...just like your traditional smiths. And they don't ever cast those annoying magma bolts when you end up massing HI against supercombatants.
A lot of folks don't like to use eyes of aiming on their good commanders. I sprinkle them liberally on my blade winders. (But not everyone casts blade wind. About half the priests get scripted with Sermon of Courage.) The ones with blade wind get earth boots and eyes of aiming. I don't think that really makes them look like Toys R Us. Because you have to have earth magic to use the boots...and that isn't all that common among the other races' magi. Sure...Pangea and Vanheim will like earth boots, but they don't really need them.
And I would love to watch a powerful assassin get two eyes of aiming. Of course, the owner of the assassin could prevent that by just having two misc items on the assassin already...but if the assassin dies I will get those.
The variety of items your IF priests can craft, especially with items that increase their random, is astounding.
You can get into blood magic with random blood magi. It's really cool to play IF once you get your research up a bit. And independent magi are still as good as they always were.
The only picks I would go up to 4 in with IF are earth (2 benefits: reinvig for your magi and makes your pretender immune to the air spell that takes commanders to the caster) and death (lesser fear on the black templars is nice and I think you will pick death 3 anyway to make sure you find the death sites because you really need death gems for research).
IF may not work that well in MP, but it's really enjoyable in SP. A lot of the nicer spells in certain spheres, such as air, do not require more than 1 level of skill. Orb lightning. That false horror spell.
One question: can rocks attack? Or just defend? Because the preaching of IF is so good against hostile dominion that you can easily put a rock in +3 (for you) dominion to reduce his hps and kill it.