Also would have died only cause Luffy. The whole drowning situation was only to punish Luffy.
How much times would Luffy have been dying without any fodder around him helping?
Kid went against Shanks, went into BM Territory, went against Kaido, never begged down and is still around going against Kaido himself. And you consider that weakness?
About Killer getting a clown... Kid is there to take revenge for that cruelity. Also, Killer was still able to take down Zoro back then, even as "clown".