James Gunn changed a lot about Yondu as he adapted him from page to screen.
However, it wasn’t the core personality changes that seemed to bother fans; it was the short and stubby fin worn by the character to guide his Yaka Arrow.
In fact, the character is almost unrecognizable in a few key ways now that Michael Rooker has become inextricable from the part.
As you’ve already gleaned, certain fans didn’t love it.