Here is the reason I personally dislike Fender designed instruments...
THIS IS MY PERSONAL OPINION AND YOU ALL ARE ENTITLED TO YOURS. I WILL NOT BASH YOU FOR LIKING THEM AND I EXPECT THE SAME FROM YOU.
1) That neck heel block. I can't play comfortably past the 14th fret.
2) The bodies are very large and chunky. To me they seem heavy and are not designed to balance the weight like Warwicks are.
3) The pickguard. I took the pickguard off my jazz and it was infinitely more comfortable to slap, but it was ugly.
4) Quality. The neck pockets on ALMOST every non-American Fender I have seen have been sub-par. Many times the pickguard doesn't line up with the control panel, and that bugs me. Every Fender I have played has felt cheap. Once again, my experience and opinion.
5) Price. For the price of an American Fender I can make a Warmoth jazz bass that is the same exact thing aesthetically but more customized to my preferences. Example: Stainless steel fretwire.
Don't get me wrong, I love the way they look and sound, but I don't feel like it is a good trade for playability. Hence Warwicks are my favorite basses, even though I don't have any

(I have owned one though but it was not in good enough condition to warrant the price I payed) though I am buying one off of eno shortly.... YAYYAYAA
Once again, this is my opinion and you are free to have yours.