They doomed themselves. We could've had nice pen-and-paper style encounters in dungeons, but reading text boxes is obviously not immersive enough for Bethesda's "core fans." You could wedge boulders with a strength check (or alternatively, try to move them with magic).
Why so outdated? There's no need for textboxes or alienating your "core fags".
How about this instead:
1. You need some attributes (don't throw them away you moron!) and physics engine (ok, you have that one), you will also need most of your old spell system.
2. Make it so that while one of the move controls is pressed character accelerates in that direction at rate dependent on strength times traction divided by the sum of mass of character's body and inventory, until it reaches velocity determined by their speed score, make this work via forces acting on character's body in simplified manner as if it was a point mass (you don't want it ragdolling and you probably don't want to go overboard and make a successor to Cortex Command although that would be nice) - you already have engine that can do that pretty much automatically.
3. In any physics engine boulders will have mass and there will be certain minimum amount of force that's needed till object resting on some surface starts moving on given surface of given inclination.
4. Because of 2. and 3. pushing against boulder will exert force proportional to character's strength, which will make it budge or not depending on your strength score.
5. Casting feather on the boulder will reduce either its weight or mass (preferably the former) so it will be easier to move due to less static friction.
6. You don't need fucking textboxes, or scripting, you just drop the boulder of desired weight wherever you want it in the world and it will work, complete with visual cues regarding how well player is doing courtesy of your physical engine you already have.
while cleric may piss off his god by using non-blunt weapon against people (nevermind that the source of this restriction was horribly off to begin with)
Well, it does make sense... kinda... if you look at the historical source. In the common Latin translation of the bible, "thou shalt not kill" was written as "thou shalt not spill blood", therefore catholic clerics who went to war for their liege used blunt weapons because they're less likely to spill blood. Therefore no sin when killing. MAKES PERFECT SENSE DOESN'T IT?
Well, OTOH Catholic clergy, including archbishops, didn't have any problems running around with fucking swords and other sharp weapons during crusades, and if you brain someone with a mace they will likely splatter quite a lot, even if it isn't spiked or flanged one.
although actually a mental blockade and breaking it could be a cool thing from a lore-based point of view, see e.g. Wellington Yueh's Suk conditioning in Dune.
Keyword being "breaking".
If it has a skill it should govern mobility or potential effects on fighting skills, not the effectivenes of the armor.
It would still be hard to control growth of the skill in use-based system. Use based and passive skills simply don't go together very well.
Use-based works best with skills that have assessable success chance for each use.
This can be easily governed by the total amount, type and maybe position of metal - noble (or maybe non-magnetic, or whatever you prefer) metals might be ok, an iron helmet on your head might be worse than an iron boot. A ring or a small necklace will be negligible.
As long as it leads to an interesting mechanics rather than derpy "no, u cant" - why the fuck not?
Other materials are indeed a good idea, maybe with the exception of restricting movement which might be necessary to cast some spells.
Or to perform adequately in combat.
Finaly, there's also law/tradition/pride.
That's shitty excuse because it doesn't account for outliers and, if forbidden combo is extremely practical (and balancing effect of forbidding it conversely most useful) then the law/tradition/pride would quickly yield to obvious superiority of the opposite or be crushed by those who are less lawful/traditional/proud, but more opportunistic and generally smarter.