First of all riku didnt have aphysical form.He was just heart that was able to project its human apperance but he wasnt physical at all.Second a heartless is abeing of darkness that has discarded its body yet it has some sort of "matter".Kairi just purified soras darkness.So sora at that point is just a huge pile of light energy that materializes into a body.
Back to topic ,riku in KH1 was weak and exploitable so if his heart was forced out , considering his rather low spiritual reasistances,a heartless should be created.
A) I never said Riku had a physical form,
not once.
B) Heartless aren't "matter" they are "darkness made real". This is explained several times in kh1 and even Yen Sid says it in KH2. Being made of darkness and being a heart projecting a physical form are two different things entirely.
C) We don't know what Sora was, only that he was physical. His physical form and the one Riku had in that one final mix scene have not been explained. We only know they was neither heartless nor was they in their bodies.
Wrong again. Riku was exploitable but he wasn't weak. He was worthy of a keyblade, he was able to wield darkness, and he was even considered worth Ansem's time. Riku's heart was far from weak and always has been.
A heartless by the way is born from a heart consumed by darkness, being kicked out of his body did not make Riku become consumed. The very fact you see him walking around with a human appearance shows this. To think he formed a heartless is just ignoring facts.
He lost the keyblade 2 times because he was valurunable to darkness.He couldnt have that much strenght in his heart to fight back.
Also the brown cloak is just a brown cloak.Its not a hooded man its just a floating hood XD.
Incorrect. The keyblade doesn't give a damn about darkness. If it did, MX wouldn't be able to use one, Terra wouldn't be able to use his, or later Riku in KH2.
What caused the keyblade to abandon Riku was his choices. Also Riku only lost his keyblade once.
The first time Sora got it he didn't truly own it.
Wrong again, there is definitely a form of something under that hood: