Absolutely!
Whenever we're busy, a guy/gal who sounds like a pro and can say it and receive it quickly and concisely is going to have a better chance of getting what he/she wants. Likewise, someone familiar with local procedures and common reporting fixes has a better shot.
A pilot who blocks vital R/T time with useless drivel and lots of "uhs"; OR who we have to pry the necessary info out of by asking a dozen questions; is not someone you want/need on freq. during busy periods.
Also, there are certain things which ATC is NOT supposed to have to ask about or solicit. For example, "Are you requesting a SVFR clearance?"
