PAc is one of the best either ... so we are talking about something exceptional in the history of the human kind
RJJ handspeed is faster than Pacquiao's. Heck, Amir Khan has faster handspeed than Pacquiao. What makes Pacquiao fast is not just his handspeed, but also his footspeed, which is a deadly combination especially when punching from angles with combinations. People should not confuse Pac's overall speed with handspeed. Other fighters are faster than him in terms of handspeed.
When you have a long slim frame I believe it gives an illusion that you are faster than another person who has midget like proportions even if the speeds are the same IMO.