Assume Piccolo hadn't merged with Kami

[ahill1]

And he found a way to get that strong through other means.

Do you think he still would have offered Vegeta a hand post the CGs battle?

Or recognized Vegeta's value at the end of Boo's arc and say "Vegeta doesn't feel like Vegeta!!"? Or he'd be more closed and reserved to things like these?

 

[SSJ2]

Maybe. Kami definitely influenced his personality and mellowed him out, but I'm not sure if it would have changed his character in those moments.