They've been disabled for a while now...
And they'd be kind of broken assuming you get the right MvPs...so I'm pretty sure it's staying that way.
If a certain guild wants to spend a few million to defend with castle with MVP's, why not let em? A good WoE guild is participating, they should all be able to take out the MVP's and get the castle before the time is up. What do you think all those SQI's are for? 
Exactly what I'm thinking.
@ Dreamer, how is it broken? You could have a tanker to lure them away.
Seriously, it's just... It's been allowed for
years, what I think is broken is that I just spended 22mil for something that got disabled from one day to the other. (I know it's been for awhile now, but I only noticed it yesterday.)
So I still need a answer from a GM or PR. Will it ever be changed back or not?