#1 - Not really, that route is already faster and provides protection from Assassins, so making it easier to get into would just make the other route pretty much obsolete.
#2 - Kind of agree and disagree at the same time. I think wallride would be too much of an "easy mode" but definitely something has to be done there. Maybe lower the angle of the approach, aka you can see that part a lot sooner, rather than having a blind hill and going "I'm screwed" because you didn't have a perfect line through that crest. Also does that ramp even needs to be there?
In any case that's probably the most annoying part of the track as you effectively have to learn that one trick to go about it, otherwise you'll most likely crash if you won't slow down (and it's hard to tell that you need to slow down there). Aka it's down to knowledge, not skill per say.
I always use the shortcut route though
#3 - Agree here fully. That's the most pointless route of them all. Unless you literally know it's there and are planning to go through it... you can't get into it. And even then it slows you down a lot and the speed pads don't help at all. To make it worthwile, you'd need that route going through those rocks and rejoining with the main one around that banked corner, otherwise it's just slower. Pickups won't change that, as by the time you'll finish doing it, you'll be almost at the next set of pickups anyway.