I'm increasingly thinking that this discussion gets off the rails for taxonomical reasons. "Fast" may ultimately be the wrong word.
Imagine:
i) You're standing at a bar, signing a credit card slip, without resting your forearm on the bar.
ii) Same as (i), but a rope is tied mid-way down your forearm with a 50lb weight attached.
Which signature will look better? Answer: (i) - when your muscles are flexing under high load (as in (ii)), it is more difficult to be subtle. I'm obviously metaphorically alluding to your question (b) - "...is it easier to be technical?". Yes. If YOU don't have your muscles under max load, or your joints locked, it is easier to be "technical".
Back to your question (a) and your use of the word 'fast'. In my mind, this is about a combination (compromise?) of the ski's surface area and stiffness. When I was about 13-14 years old, I was about 135lbs, and skied at 34mph on a late 70s, pre/non-graphite 63" Connelly Shortline. It had very little surface area and very little stiffness. It could turn on a dime in ways modern skis can't imagine. On the other hand, I could come out of the ball with significant angle, the ski would "dig in", but it wouldn't translate in to speed (certainly not compared to modern skis) because I wasn't leveraging my body position against either surface area or stiffness. It was a really, really "intense" experience (in my mind, it felt 'fast'), but it wasn't "fast" (at all) as you might use the word. It was a very slow ski. Because I'd be feeling maximum load in my muscles (leaning/leveraging, physically "stiff", trying to generate velocity with a ski that was neither rigid nor had large surface area), as per my bar-signature example above, it was unlikely that I could be technical or subtle.
Does that help?
http://images1.americanlisted.com/nlarge/connelly-short-line-slalom-ski-75-picture-rocks-americanlisted_15008297.jpg