That'd be good and all, but...
That system only works with in-line spoilers (and you can do that now anyways, people have in the past, by simply using the [color] tag). It doesn't work for images, or, if someone is posting a large spoiler filled review, you wouldn't want to scroll through a page of blank nothing if you wanted to skip it.
Personally, I think it's fine as it is, but I wouldn't be opposed to having two different tabs either. I don't have a really strong opinion on it one way or another though; just pointing out why the TVTropes style wouldn't work here.
ʕ•ᴥ•ʔ"Stop watching anime. it makes you think all girls are incredibly hot and shy, and there are 10 that all want your boner which just isn't true." -Brik-aniki
"I CAN'T HELP IT THAT I WANT TO EAT MY OWN VULVA AND SHARE IT WITH A LOVED ONE!"-Reichu
"I have a fetish for naked women with stigmata playing ping pong in the mud. Is there a name for that?" -Kaiser O-Ornette-dono-sama
“Don’t do that; that was probably hooker money.” -SSD on me holding money with my mouth