Addendum: Can we please have an option to disable or have to HOLD the B button on the left (or either) controller while drumming? I tend to unconsciously rest my thumb on it and sometimes press it on accident, especially during SLOW sections (because I guess I "follow through" a bit further and occasionally end up 'punching' my thigh, and the feedback causes me to press down on the button, I think? Either way, make it a "hold 3seconds" or "press BOTH buttons on one controller" or "press B on BOTH controllers" and I'll be a happy player :) )

Edit: Even better: move the "pause" to a stick press. I don't think anyone would rest their thumb there while drumming?

Hi! Thanks for your extensive feedback!
I'll attempt a reply to each of your questions.

At the moment, you can drag drum pieces around and put them higher or lower, but as you noticed, you can't tilt them. We could add an option for that in some of the following updates. Thanks for asking.

You can already arrange track positions by moving the drum pieces around! You can move the floor tom to the rightmost position, and the track will automatically align to the new position and become the fifth track instead of the fourth :)

Holding either drumstick with a different pose seems nice. We could add that to one of the following updates.

Stop sliding while holding a fret on the guitar was an option that we found more confusing to use than it seems to be in theory, but it may still be a matter of preference, so we could still add that in the future.

The option to hold both buttons (trigger + grip) on the left hand when you only have to play the 'right' half of a fret may seem "correct" if you think it is like holding a single string on two consecutive frets. It would help if you thought of it as holding consecutive frets on different strings.
Furthermore, having that option would reduce the number of "chords" to 2 from the 3 combinations we currently have (trigger, grip, trigger + grip).

About the game being VR only, we're considering making an official flat version of it, but we'd need to rework some stuff to have it "production ready". The game already starts without an active VR HMD, and it's playable without it. You can navigate the menus with a mouse, keyboard, or controller, and everything should play just fine. We don't consider it "officially supported" because the game has been written with VR in mind, and currently it's not 100% feature-complete and polished to play without a VR headset.

About the pause button, you can already change the binding in the SteamVR settings, but we could consider changing the default to stick press, as you suggest.