I got an official reply from James on the interaction between Iron Discipline and attachments. I posted it in the rules forum here.

Thanks, Clamatius.

To Cyberfunk - why would you have to choose between Innovation or Pilgrimage (which imho isn't that great of a card for what it does)? And if you did have to choose, I'd take extra free Resources any day over what Pilgrimage offers (dependent upon your deck theme, of course).

I don't think you have to choose between them either - I think it's possible to run both. But I suspect what he's saying is that he only wants to commit multiple developments to the kingdom, not kingdom and quest. Pilgrimage seems potentially playable for Empire because it gives you more temporary unit disruption. You have Forced March but that's really about it.

Forced March to send your opponents Kingdom units to the Quest Zone and Pilgrimage to move any attachment heavy units in the Battlefield or Kingdom Zone to the QZ. Choke his resources, limit his attacking forces and give him a mit-full of cards he can't use. Toss in Infiltrate! and you are looking at a serious cause for min-max combo decks. Use Bright Wizard Apprentice and Iron Discipline to counter their attempts to disrupt your own activities.

Pilgrimage is pretty darn good in a lot of spots. At worst,
it's a Seduced By Darkness with lopsided barrel attrition. At
best, it's shutting down an 8-hammer Johannes, resetting an
irritating quest, or bouncing their biggest guy in combat while
you mop up the weenies. It can be played during your opponent's
turn, unlike most removal. Orcs can use it in conjunction with
Troll Vomit and/or Lobber Crew for a mid-game lockdown.

You *could* try to play both Innovation and Pilgrimage in some decks.

Orcs, probably not... the thing with Innovation is that it isn't really that
good unless you draw more than one (or were going to develop
anyway). If you just play three unnecessary developments and
burn a single Innovation for three, you could have just put the
guys that drew those four cards into Kingdom rather than Quest.
Orcs in particular just don't have a lot of reason to develop
early (save against Empire, where they have to spread it
around). I think this makes it hard to run both cards, and I
think Pilgrimage is more likely to be relevant by the time Orcs
start tossing down developments in earnest.

Chaos could perhaps get away with running both. I do like the
idea of generating resources out of turn for a suprise Valkia
or Blood for the Blood God (or, indeed, Pilgrimage). They are
rather tactic-heavy anyway, thoough. My gut says it's better to
go one way or the other.

Pilgrimage is only a so-so fit with Empire, since Forced March
is better with Verena, and Empire virtually always develops the
Kingdom with a Shrine. Pilgrimage is sometimes playable at 3,
but Empire has better options.

Dwarves are probably the best fit for trying to run both. They
will take the game late and develop everywhere. And, they could
use Pilgrimage to complement the Kingdom-choke of Master Rune
of Dismay, etc. They could even bounce their own guys to
trigger the "leaves play" text on Zhufbar Engineers/Dwarven
Ranger.

So, are we far enough off topic yet.