There are a few established somewhat inland higher end OC communities that could provide a reference point for where shady canyon prices could head. So we'll include communities with large premium homes (3k sf- 10k+) with large lots and no ocean view. Off the top of my mind, there are three communities that fit the description, Dove Canyon/Coto, Nellie Gail and Ladera Ranch Covenant Hills.
I do think that Shady Canyon is 'special' and has some things that will allow it to be the highest end inland community.
1. Very quiet and private
2. Large lots (although not >1 acre like some in NG and Coto)
3. Very close to job centers in Irvine
Although I think the fact that Shady is not equestrian hurts a bit. I'm not sure why they made that decision, but i think it adds a bit of value to the homes in Nellie Gail and Coto
Now, if you're a long term buyer and are looking in 20 years time where will it be? I think the premium over the established communities will have worn off and it will end up with pretty comparable costs per sf. for all three communities (coto, NG and SC), and Ladera trading at a discount