Personally, I kinda like this. I hope they'll let us "upgrade" into it - I'd be willing to pay an extra $25 to get those summer weekdays. (I'm local now, and hitting the park roughly once a week - it'd be nice to keep that going.) But I'm a little bit worried they'll consider it a crossgrade and not allow that. I guess we'll see in January.
The only thing I can't figure out is why they didn't simply change the blockout calendar. Everything I've seen suggests that that's the only major change. (One blog was noting that the parking discount was now only valid at Toy Story, but it was already like that.) I had to wonder if they were doing this to avoid setting a precedent that blockout calendars can be changed after they're announced.
(And/or to give themselves a chance to grab another $25 from existing Enchant Keys.)