Well for one, I use a trackball, a Kensington Expert Mouse. I've used them for 20 years and on my 3rd one. I literally hate mice. KEM as a scroll ring, I can map a middle click to one of the 2 unused buttons, but to effectively use it, I have to use 2 hands... If there was an option for rebinding a middle mouse click to a key, that would solve the problem. There is no such thing. I see no reason why there should not be an option for legacy VAB controls... Old keyboard controls using the arrow keys and + /- worked well and were intuitive.
I am Incredibly disappointed in this release after 3 years in development... Early Access or not... If this is what they came up with in three years, I don't see this getting much better anytime fast, if ever... Performance is also an major issue... Ryzen 9 5900X, RTX 3080TI, 64GB DDR 4-3600... Any large rocket launching is abysmal with low FPS. After about 10hr's in, I really just want to cry...