I'll go devil's advocate here and argue for lighter. IMO, this question is more about style than size or skill set. I've realized over time that as I get better I evolve toward finesse. In variable snow, where I used to just blast through on Heads and Stocklis and Volkls, I now slice and dice on Kastles and Nordies and Blizzards. These are still moderately stiff skis, and moderately damp, but they're lighter and quicker edge to edge and for me seem to fit SJ's dictum from last season that skis that are well-balanced in longitudinal and lateral stiffness will just feel better.
Not arguing that as we improve we should move toward lighter gear. Just saying that IMO there are three attributes of lighter setups worth considering:
1) if you geek out on technical skiing, with a lot of on-slope attention to edge angles and CM in space and all that other stuff, then a lighter setup may be the ticket. You better pay attention in stiff chop or you're toast. And if you do it right, then it's silly easy. Immediate reinforcement.
2) Most good skiers end up, sooner or later, increasing the amount of time they spend hiking, and perhaps after that, skinning. A pound or two may not seem like much until you're hauling it up a 40 degree rock band at 11,000 feet.
3) And just to stir the pot a bit, I think beefy gear can become a crutch. The gear does the work instead of your mechanics. No, not saying that everyone who uses heavy gear is lazy. Does not follow. Rather that, it can allow advanced skiers to ignore that last skill set that will get them to the next level. Consider how many skiers do not or can not bend their skis into a new radius when they carve at lower speeds. They just follow the arc of their sidecut. IMO, a heavy stiff ski allows that to happen more easily. It will also stabilize you better at speeds over your head. Which may or may not be a favor...