Has anyone considered that we might not have Legendary mascots this go around? This is something I've been pondering more and more as we speculate. Simplification of the plot would mean no Legendaries, in all probability...and the first gen titles, which they're supposedly going to be drawing from in some fashion, had the starters as mascots, rather than Legendaries. Whilst the second gen had Lugia and Ho-Oh, neither of those played a role in the story either.
So, what if DO get Solrock and Lunatone as mascots to tie in with the region's motif - whatever that may be - and don't get mascot Legendaries instead? Or what if the games don't have mascots at all? It seems unlikely, but I think it'd be interesting to see how these games would be seen without the cutpasted half-arsed Legendary Pokemon plotline we've been forced to endure since the third generation.
There are a ton of fantastic ideas they could take inspiration from...but would you really WANT them to do so, when it's almost a guarantee that they're going to receive the same lack of development and exposition as every Legendary that has come before them? They're always Eleventh Hour Superpower or Doomsday Weapon creatures you capture just to keep the bad guys from getting their grubby mitts on them. If that's going to happen again - especially if the designs are as amazing as they have been in the past - I think it'd be better if we didn't have mascot Legendaries.