About the the only thing unconventional about shots from a spaghetti racquet were that it produced twice as much spin as a conventionally strung woody, and launched the ball higher off the strings. Combined, the higher rebound angle and extreme spin produced ball trajectories and bounces that were very surprising to those who hadn't faced it before. But the reports of the racquets producing wild or unpredictable spin are greatly exaggerated; the spin was just much more extreme than anything player's had seen before. Eventually players would have adjusted to the arcing, high-bouncing balls it produced.
Usually, yes, more spin means less speed. (We should probably keep the word "power" out of this, as it just confuses everything. The unit for power is the watt, which obviously doesn't do us much good when talking about shot speed and spin.)
However, Wilson is claiming that these "Spin Effect" frames produce more spin and speed for a given swingpath and swingspeed. The extra spin is produced by the more rapid snapback of the main strings owing to the reduced number of cross strings, and the extra speed is probably a result of the fewer cross strings as well. Fewer cross strings means a more flexible (less stiff) stringbed in the direction parallel to the shot, so less of the ball's energy is lost in ball flattening, which results in a faster shot. (This would be similar to switching from full copoly to copoly mains/gut crosses, in terms of shot speed.)
(Note: The on court results that have been reported, like Drak's in the OP, might show that the 99S produces more spin and about the same speed as some other racquet, but we can't conclude from that the 99S does not, in fact, produce more speed than the other racquet because we don't know precisely the racquet-head speed and swingpath of all of Drak's shots during the playtest.)
If Wilson's claims are true, pros could benefit from this tech, as more spin & more speed would be very useful for any player, no matter how good, as long as they could control it. However, Wilson is claiming that the spin boost from 16x15 is not so dramatic with top-level players, so maybe it won't be interesting to them. My guess, though, is that if Rafa strung one of these up with his RPM Blast about 15 pounds tighter than his usual tension he would have a smile on his face.
Cool. Looking forward to reading how it performs in a match.
Yes, it is the mains sliding and snapping back that provides the extra spin. This was well established by about a dozen papers published by TW University two years before Wilson announced their new "technology". If the mains are "moving", in other words, if they are getting stuck out of position after a shot, they are too loose. Avoiding this will be the key to control with these open patterns, just as it is with copoly strings in general. As the TW Professor showed in this paper
, if the mains are not stiff enough they will slide too far to snap back in time to produce additional spin. Instead, they will raise the rebound angle hugely and may actually reduce spin - the result will be a very deep, uncontrollable ball that doesn't drop as expected because it doesn't have much spin on it. (We should probably be on the lookout for this when reading reports about these frames. Based on reports from people like Drak, who have played with them strung up properly by Wilson, we know that they are controllable. If someone posts a report that they were launching balls all over the place, or that the frame was a "rocket launcher" we should probably suspect that their strings weren't tight enough.)
Anyone playing with these frames should study that article closely to help find the right string tensions needed for control. One of the things that the paper suggests is that anyone considering a gut/copoly hybrid in a 16x15 should be prepared to string quite a bit tighter than usual. Otherwise, the extremely flexible gut will slide so far in these patterns that it will never have time to snap back before the ball leaves the strings.