Don't get me wrong, the hair pieces that have been released in recent years are great, but I feel like I've explored the design variations of the existing pieces to their limits. And I always want more variety.
For starters, I would like to see the existing hair pieces (except maybe the Princess Leia buns) in a wider range of colors. Often, a new wig design will be created for a particular licensed character, in that character's hair color, and not used for anything else. This seems like a waste of the time, effort, and money that went into creating the mold. Plus, TLC misses out on opportunities to create distinctive "characters" for their non-licensed lines by over-using the generic wigs like the ponytail instead of getting more use out of the unique styles.
At the very minimum, every wig design should be available in black, brown, orange or dark orange, light gray, and tan, to cover the basic range of natural human hair colors. If TLC doesn't have a specific use for a given style/color combination, they can always put them in Pick-a-Brick. I'm sure all of us AFOLs would eat them up.
As for new styles, I really, really would like to have a hair piece with a topknot or bun that looks better than the godawful Islander hair from the old Pirates line. Something I wouldn't be ashamed to put on a Far East-inspired minifig, or on a little old lady. (Really, Aunt May? A ponytail? Since when?) Speaking of ponytails, I also think it's high time we had one tied at the nape of the neck rather than the crown of the head. (No, the Qui-Gon wig doesn't count.) A single long braid would be nice too. And again, all of these styles should be available in at least the five colors mentioned above.
So what do you think? Any other ideas?