Do caster out of combat options matter?

[Lvl 2 Expert]

I feel like the problem in the opening post is mainly a problem with certain high level spells, and doesn't come up as much at lower levels

In our campaign we came upon a huge wall of thorny roses. That's not an obstacle the DM could only use when the party have spell X. You can defeat it by casting fly on the strongest character and have them fly everyone else over, or you can try burning a hole through it with fore spells, or you can tunnel under it with Mold Earth. A burrowing or flying wild shape form could work too, you could even Conjure Animals burrowing or flying creatures. This is an obstacle that will basically work in any game, even an all magicless martials party should eventually be able to get through it, even if it might not be pretty. They might be able to climb a tree near the hedge and lasso a tree on the other side so they can rope over it. (With the right knots they can even recover their rope.) Or maybe they can chop a tree near the hedge down and drop it on the roses, see what that does.

Is it a hard obstacle? No, not really, precisely because there are so many options. But if you want it to be harder combine it with other stuff. Maybe have some flying enemies that stay hidden behind the thorny wall and only attack those going to the other side. Fly-carrying is now pretty bad. You could have the rose wall appear inexplicably in a cave, where any flying solution won't work. Maybe have them be chased by something big, the rose wall might be this world's version of the Jurassic Park fences. Now burrowing is harder because of the time pressure, someone needs to distract the monster while the digging happens. Burning through the hedge is also much less inviting now, that might just let the monster out.

I agree it gets a lot harder to design good scenario's as the magic gets more powerful. How do you design a scenario where planeshift is part of some solutions, but isn't the one and only solution? I mean, technically I guess you could planeshift around a wall of thorns, shift ones, walk 100 meters, shift back. But that just feels like a silly excuse to use your powerspell. (Also: it doesn't actually work exactly like that with the spell as written, but you can just try to skip much of your journey and shift back to near your destination.) But that's a problem with certain powerful spells, not really with utility magic in general.