[PvK]

Overall I like your thinking, though I see some of your points differently, so I don't think Iron Faith is really weaker than Ulm. Specifically:

Originally posted by Sandman:
...
Iron Faith is forced to take drain 1, but the black priests are not drain-immune, so their research ability is dreadfully weak. A higher drain scale would make them even weaker, so it's not really viable. This means that compared to normal Ulm, Iron Faith has, for all intents and purposes, a cost of 80 design points.

I disagree. Your logic does pose a question for design, but I think Drain 1, 2, or 3 are all valid choices for Iron Faith. The reason I think so is that with the new priests, they have more access to research-boosting items, and Ulm generally researches Construction and has forge bonuses, so they don't need to get strong research from priests. My Iron Faith games tend to have cheapo summoned or indy mages doing the research, laden with research boost items, which easily overpower the drain penalty. My priests rarely research, anyway - they're all forging, casting, and supporting field armies.

The second sacrifice is the lack of mage with 2+ in any field of magic. Sure, there's a chance of a 2 earth black priest, but only 1 in 8. 2 earth opens the gateway to all sorts of neat stuff: earth boots and then dwarven hammers, assorted earth summons and lots of useful spells that are reasonably synergistic with the units of Ulm: blade wind, legions of steel, strength of giants, gnome lore and the very handy earth power.

This is true, but regular Ulm has zero variety in its natural mages. Having a random is very different and, in my view, at least as useful as the 2-earth on the smith. It's just not the usual Ulm thing. It does tempt the pretender to take 2 or more earth power, but that's an interesting design dilemma, and not, I think, a worse weakness than the random pick is a bonus.

Apart from the 2 earth black priests (which are very valuable), other black priests are left casting personal/one-square buffs or very limited attack spells, with no fatigue reduction.

Or, in battle, casting holy-3 spells. Mainly mine do construction, and also I have my pretender or other mages which become available, forge them some power-boosting items, at which point, suddenly they have all sorts of uses, particularly with their forge bonus. It's not automatic, but it's just a step away - there's a lot of potential there that standard Ulm doesn't have, or not as easily.

Iron Faith's default spell is still legions of steel, despite having to research to con-4 or conj-3 to have any hope of casting it.

With the priests, true. Though, they will almost always research Con-4 in order to make good use of their forging bonuses.

...
The usage of sacred units allows bless effects to be usefully employed, as well as reducing gold spent on upkeep. Two black priests cost the same upkeep as one smith, which is just as well, because they have only one more research point between them.

Right, and Black Templars also offer similar savings over Black Knights.

...
As well as the templars and the priests, there's also the rather useless black acolyte. He costs 10 less than a normal priest, but is otherwise identical. I suppose he keeps your army colour coordinated.

Rather useless? Ordinary priests are useful, and 20% savings is not bad. Color coordination is always nice too.

...
Additional sacred troops are another possibilty. The obvious candidate is the Guardian, who I can see little reason to build as Iron Faith, when sermon of courage is readily available, and black templars are more powerful.

I like Guardians, and would enjoy having a sacred Version to play with. I do build them in my Iron Faith games, because they are a much different kind of unit from Templars, and are cheaper.

As for your suggested improvements, I don't think Iron Faith really needs any, for the above reasons, however I would like to see a Templar commander. That alone would be a meaningful boost, because Ulm is generally an item factory, and this would give them a strong blessable fighting unit which can also have items. It sort of seems like an omission to not have a Templar commander, but maybe IW thought it was an interestingly ironic limitation (which it is).

An expensive (over-priced because it would fill a vital niche) capital-only earth-2 priest is an interesting idea, though as I wrote above, it would remove an interesting dilemma when making the pretender, and I don't think it's really needed. I do like the flavor of your other suggestions, but for the above reasons, I don't see them as necessary for balance.

PvK