Okay, so far these Doorways don't really feel like their own card type. I'd like to try workshopping something a bit more radical. Feel free to toss ideas into the pot!
•Helm's Deep Doorway Doorway
When you play Helm's Deep Doorway, stack a battleground from your adventure deck here.
Response: If a Shadow player is about to take control of a site, discard Helm's Deep Doorway instead.
This doesn't make any sense. Stacking a site onto a Doorway works thematically but what happens when it's your turn to play Site 4 and Site 4 is stacked on the Doorway? Let's try...
•Helm's Deep Fastness Doorway • Fortress
While the fellowship is at a battleground site, each character bearing a
weapon wins skirmish ties for strength.
If any Shadow player takes control of a battleground site, that Shadow player may discard his or her minion to discard this doorway.
I added
Fortress as a sub-identifier, presuming the existence of other doorway keywords - maybe Home, Hidden, Lair, etc.
The game text makes slightly more sense now but the wording on winning strength-ties was written without precedent from other cards. It can probably be worded better. I like the idea of the opponent having the power to voluntarily destroy your doorways and maybe it could work elsewhere, too.
•Window of the Sunset Doorway • Hidden
Each time a Shadow player plays a
or
minion at a forest site, you may reveal a Ring-bound ranger from hand and add
to exert that minion.
If any Shadow player takes control of a forest site or kills your companion, that Shadow player may remove
to discard this doorway.
But it still doesn't feel like its own card type. And where does a doorway even play to? I don't want them in the support area since at that point they're just fancy conditions.
So... what if.
•Window of the Sunset Doorway • Region 2[T] • Hidden
Each time a Shadow player plays a
or
minion at a forest site, you may reveal a Ring-bound ranger from hand and add
to exert that minion.
If any Shadow player takes control of a forest site or kills your companion, that Shadow player may remove
to discard this doorway.
Hmm. So now this doorway plays onto site 4[T], 5[T], or 6[T], necessitating the fellowship to have at least gotten that far down the site path before you can play the card. That's certainly different, and it restricts the doorway's effect until half way through the game. Now it feels different from conditions, but maybe it's useless now.