Good idea! I had felt the same way about the checkpoints and I ended up increasing the size of the hitbox quite a bit but I like the idea of expanding it to the whole platform much better. Creating something on this scale without tanking performance or getting into heavy duty LOD stuff was a fun challenge, so I'm glad you appreciated it. :)
The character has greatly reduced (though still some) control in the air which is part of why it might feel pretty floaty. There's definitely lots of room for improvement there and feedback like this is very helpful so thank you!