Hmm, I thought I had already suggested the following but I guess not. Probably only ever thought about it in my head
How about a way to customize the restriction to view spoilers?
When someone uploads, for example, rare things, volumes, jcafe exclusive stuff and the like, some people (or maybe it's just me ^^) would perhaps like to be able to restrict it a bit more than just needing an account with 1 post.
It would preferably look like the following:
[spoiler ren=1 post=2 reg=3]Blah blah blah[/spoiler]
A user would therefore need a minimum of 1 Renommee, 2 Posts, and be registered for at least 3 days.
Another example would be when someone creates a mirror for an already existing upload and restricts the mirror more than the original upload which has the default restriction. Therefore when the first link dies you could resort to the second, more restricted one. And if you can't access it... well, it might encourage people to not be just simple leechers ^^
A convenient option imo.