An Idea

[Smeagollum]

Hey the idea is good, we just need the right phrase. My English ain't that good. So, I leave that up to you people

[Thranduil]

Maybe "This card's twilight cost is except when it is played.  When played, you choose the value of X."?  Does that help?

My wording's slightly easier to understand without experience in other games, but there are some situations where it would come in handy to have that form.
My Fellowship block deck would have an example if there were an X-cost Hobbit.  Maybe that removes a burden (or 2) if you cannot spot X burdens.  (Meaning that you have to add more twilight than you have burdens to remove them)

Those are both very good and interesting ideas. to you BW!

Thanks for everyone's thoughts on this. I may return to this, or have new idea sometime in the future.

Thranduil

[Beregond25]

I'd think it'd be rather redundant unless you made this sort of card:

Gollum's Desire
Event • Manuever
(You choose the value of . Except when you play this card, its twilight cost is ).
Add X burdens or X wounds. Discard Gollum.

Still OP. I mean I play with people who give me tons of twilight and often move on. All you would need is 22 twilight and you win. (2 for gollum 10 for card 10 for x adding 10 burdens)
Maybe a bit more for some cases like the 12 resistance frodo phial of galadriel the box thing Etc.
I think there should be a limit of 5