Seriously, people that isnt skiing in the park doesnt need full twintiped skis, the big downside are the often soft flex that gives them bad edge grip on ice and the long turning radius that makes the twins pretty boring for medium to slow cruizing on groomers.
And i mean most of the "normal" people on the hill doesnt ride that fast.
But then again for example someone that wants to get better when skiing offpist skis like the Seth Vicious are more optimal because they are more forgivin then the legend pro riders with the same waist width.
But if you take a look at like all the All mountain skis they have a semi twin-tip.
And i must say that there are a few twins that hold up against all mountain skis like the Scott P3, Völkl Karma, Big trouble, Scratch BC Etc.
For exampel my Scratch BC`s (05-06) are much more stabil and have a greater edge hold then my nothing but troubles that are 2cm thinner under foot (and many cheaper all-mountain carvers and all-mountain freeride skis).
But the downside with them are the really long turning radius that many of the wider skis have, they get boring if you wanna carve som shorter turns on groomers, but thats not my style of riding anyways.
Many of the wider Twins are really good over the whole mountain, just as legends, Monsters, Bandits are.