Yeah, let's say your parents are kind of into that elderly age but can't go onto Space Mountain but you do. Well that also breaks the system in a way because you're forced to reserve for three rides and the rides are in two groups which makes things stranger too. And you're not allowed to reserve a 4th reservation until you have completed the first three. Basically, once you're also at the end of your day. There's no point of getting a 4th reservation because you're feeling held back.
The best thing about the Disney rollercoasters, there's barely any drops. If you're comfortable with Splash Mountain's last drop. You can go onto Space Mountain and Expedition Everest.
Rock n Roller Coaster in the other hand, its still awesome and its in door. Instantly right off the launch; you'll be taken into a loop but you'll see it before it happens and at least you make body feel ready for it. Everything else is like how I mentioned above.
Ill agree that I'm not a fan of the grouping of the rides. Let me reserve what I want. I do also wish you could get a fourth FastPass after you finished your first, a fifth after your second, and so on. I think that's the biggest annoyance of it. I do like the system, but I think Old Testament could use a few improvements.
I'm probably gonna try space mountain on one of these upcoming trips, honestly.
And redcrown, I don't know how you've faired on the teacups before, but it's gotten me a couple of times. My parents are in their mid to late forties and can still ride coasters fine.