As someone who actively hunts achievements in different games,
The current system of achievements we have has flaws that should have been addressed a long time ago, these tend to be underwhelming and quite frankly annoying most of the time.
Here I'll list a few of them but in general the entire system needs a rework/overhaul;

• DLC Achievements:
  It would be really nice to have separate achievements for DLC, as games tend to drop new ones with obscure achievements and suddenly your perfected game is missing out achievements.
  
• S.A.M Software:
  The software has been out there for a really long time and though it has its uses (resetting your achievements for a fresh run etc) it defeats the whole purpose of actually hunting achievements by the intended way.
  
• Rewards:
  Because of the second point above, we can't really have any reward system for perfectionists, Ubisoft for example has a decent achievement system which actually rewards players for going out of their way for them, and the rewards include profile XP, which will reward players with Coins at certain profile levels and can be used to grab basic goodies for different games. Would be nice to have a badge and be rewarded profile XP as you perfect different games, get points to spend at pointshop, etc....