You're right in that the issue is the time it takes to traverse the level, I think most of us suggested player speed first because it is an easier suggestion to make without rethinking parts of the level design and ask for another game to be made. But indeed, any trick that make it more dynamic would have made it like you suggested. Except, I also would have preferred to traverse small platforms faster, but maybe that's just me! (I can't imagine micro zip lines here and there haha, but who knows)
As for the wall-jumping controls, maybe it's either my spec or my skill, but I really found the frame allowing for a jump reset very tight and not super clear.
At first, it looks like the character doesn't stay "attached" (even though it's not supposed to attach, but you know what I mean) to the wall for long enough and get bounced back a bit, because of the collision resolving instantly. So the character is now in the air, not allowed to jump.
If the timing is intended to be short, it's fine, but with the feedback given by the game I couldn't find the final formula, almost to the point I thought it was rng