Ian, thanks once again for a very detailed and honest answer!
Geo, you have to look at the slalom boards from a little bit different perspective...
New slalom boards are made for BIG range because it is allowed to register only 2 boards per event.
Also, new slalom boards are made for BIG guys (because they are usually the fastest).
Big guys need a wide board that allows them to use BIG sail and carry them thru lulls and gybes. But they also need excellent top speed and easy control because they will use this board in very overpowered conditions.
I can see from all this above, and I can feel that every time I step on my is101, that it is a board for BIG rider. I think it is a ideal board for 90+ kg riders for overpowered 7.0/6.6 conditions in gusty winds and choppy water.
Is101 goes unbelieveable well thru chop and is very fast with bigger riders. I even used it once in severe conditions with 5.4 sail and it was MUCH easier to use than my old sonic 100 which was almost unmanageable in such chop.
I remember few years ago, Kevin Pritchard used to sail S100 with 7.6 sail in lighter winds and win races. I am 100% confident that he would choose 8.4/is122 in the same conditions nowdays, so yes, I agree that range of modern boards is shifted. But they still have much bigger range than older boards.
But I am afraid that ligher riders are forgotten in this new slalom program. Yes, new boards are very easy to handle also for light guys, but they are simply not fast enough. Lighter riders do not have problems going thru lulls and in gybes, their biggest enemy is drag. So they have to use narrow boards, smaller sails and smaller fins. If the new narrow boards (is96/86) have softer rails, I am afraid they will not be as competitive in light winds as older, hard railed designs.
For me, I am somewhere in between (80kg), and I think I was faster in light wind with sonic 100 but better overall in high winds and heavy chop with is101.
But still, I find s100 much more exciting and more enjoyable to ride!
I was hoping that I could replace is101 with is96 and get that sonic100 feeling and lightwind performance + great control of is101 in chop.