Yes, that's what Maniascript will do ^^

Tilted boosts.

THIS ^

YES, tilted boosts for platforms and GP roads, also flat to tilted transition roads for those surfaces would be great.

Other thoughts of mine:
- Lake-type water terraforming options, similar to how it worked in Desert and Rally.
- Boosters on platforms without constructions on the sides. I want me some red boost slide tracks.
- Boosters for caves and platform tunnels.
- More types of turn and elevation options for cave roads.

I have a feeling at least one of those will be added for the full version, a lot of the stuff mentioned seems like common TM blocks which can be very useful.

The 90 degree banked GP turns ... half of them are missing. Also, I'd like to see a set of banked turns that have the red part of the clip on the outside instead of the inside.

perhaps the ability to make platforms in caves?

More cave blocks. It's the most epic looking tunnel in TM history, and it has only handful of blocks. It deserves much more.

1x1 quarter loops are desperately needed, those 2x1 need much speed&space.
Following piece would be cool and something really new (most blocks are just revamps of older blocks):

GP tunnels

Highway blocks. Like 4 or 6 lanes.

some little ramps would be cool, also some more scenery blocs...