Folks claim that making persistent greater than 8 is bad. I don't know how to define "bad" in this case.
Making max-persistent-connections-per-server greater than 2 is "bad" in the sense of being a "SHOULD NOT" in RFC2616. According to RFC2119:
["SHOULD NOT" means] that there may exist valid reasons in particular circumstances when the particular behavior is acceptable or even useful, but the full implications should be understood and the case carefully weighed before implementing any behavior described with this label.
Basically, it's perceived as a DoS on the server and the unrestful spirits of Jon Postel and W Richard Stevens will be disturbed and will come and haunt you for evermore.

Peter