TLR should not be used as an example, and when forced to become more rounded by threats that can actually hurt them they will far and away outpace any twinborn.
No Twinborn can do anything combat oriented better than a radiant could, but a Fullborn can match them and not just one specific type but all of them.
Moving faster isn't going to get you the results youi want, when in motion the human body shifts, and it shifts more at higher speeds, and you will lose the fine control you want.
Weight affecting pushes is in dispute,
Aluminum works against Scadrial to, their compounders can't heal from it.
Are you refering to the shardhemet he used as a shield against shardblades?
Human terminal velocity is about 120 mph, that is equivalent to a single lashing, all without taking plate into account.
One Lashing puts them at over 120 mph (200kmph) add in multiple lashings and plate and they can be from a safe zone to blade range in seconds.
And Oaths compell them to aid thier comrads
So why does Scadrial get the time to build a large standing army, heavy artillery develop knowledge of hemalurgy, but Roshar can't do a little R&D?
But during that time, they will be isolated and alone, a time which Radiants can operate, they are dead either way.
*Lift
*Progression
I'm not sure what you are saying for that last part.
Harmony is a single Shard so there is a case for one
Allomancy, Feruchemy, and Hemalurgy are different systems so there is a case for three
There are ten surges but all but Adhesion where blocked(Lift being wierd aside) so there is no case for more than three.