Should Airborne School be a requirement to serve in an Airborne Unit?

100% Yes! If the unit is going to jump in to combat and you can't, then you are NMC and need to be reassigned. Same goes for Air Assualt, Ranger, ect.

I was a leg in a airborne unit for 4 years, with 2 deployments. I didn't ask to go to the unit, got me out of AIT, they just stood up and needed the bodies for a deployment. Being a leg didn't effect me or my job performance one bit. Other than jumping, there's really no difference between them and the leg units I was in after.

Not Army, but if you are with a Unit, you should have same Basic qualifications, to be able to understand the main mission of the unit and be an extra to help if needed at any point during operations.

In answer to the question - Yes. Everyone should be Airborne in an Airborne unit.

Yes

So if your unit is short a Medical Doctor, should we throw them out of an aircraft get injured now you are back to square one?

I use to feel like it did matter, but as my career moved forward, I felt being Airborne was more of a perk, automatic promotions point, first pick for schools, but some Airborne Units, should consist of all Airborne Personnel, to better conduct airborne operations.

I was in a heavy armored unit. I was cross trained with tanks while there. I never drove on in combate but I was prepared for what ever the unit required of me

No, I do not think it should be a requirement. There are many Airborne units full of talented people that have no desire to be Airborne. Under certain circumstances, there may be units that require everyone to be on jump status but it's not feasible to require it IMO.

beyond the obvious ability to be delivered anywhere on the planet; beyond the conversation of airborne relevance in the modern era, here are my thoughts:

Airborne is a critical skill because it teaches soldiers to do some really important things
1. overcome natural fear to do what is not logical aka to jump out of a perfectly functional aircraft at a height that would kill you
2. to follow preset instructions which are designed to defeat death and safeguard your life
3. to follow said instructions, on time, and execute preset instruction on order in the face of obvious danger and fear
4. to do so, preserve your life and those of others, over and over again

if that isnt combat training, nothing is....