Re: Pat Petrillo here!
Hi! Yes, it is normal for some things to come easier than others. In regards to the sluggishness on diddles and flams, both of those rudiments require that you a have soft and low diddles, or in the case of flams, the grace note. That will come by relaxing those notes and "dropping" them in softly and smoothly. It's basically a phrasing issue. Be sure to watch the DVD on the execution of diddles, the "whip/drop" motion..(aka...YIKES ! ...Moeller) This should help the flams.
Keep me posted...
PS..I will be back in the UK June 1-8..I will post the locations, maybe we can do lessons..