I've just started leveling my Rogue, this is where I'll post my impressions.
1. Slice & Dice should add to it's duration. Now if I have 20 sec left, and cast new one with 2 combo points, it just becomes worth 2 points, does not add. This would be useful change, when adds die and I just have those 2-3 points on them that are now lost. (see next suggestion)
2. If an enemy dies with my combo points still on him (and I switch to new target) those "lost" points should automatically add to Slice & Dice or Recuperate.
3. Redirect should have no cooldown, or just let us build compo points on ourselves. (like Monks do)
4. Our first AoE comes at level 66, and considering the state of low level dungeons (AoE fest) we're gimped. (except boss fights)
5. Tried transmogging my BoA daggers to Mace - couldn't. Why oh why?!
6. Glyph of Deadly Momentum - instead of refreshing S&D and Recup to their original duration, could refresh their duration to its 5 CP maximum duration. I can't see how this would brake anything, but leveling for sure would go smoother, since I can never (never ever) put 5 CP on my targets, they just die at 3-4.
7. Minor glyph that lets us use Spring while in ghost form (I believe monks can roll while dead?)
8. Glyph of Deadly Momentum - could work on kill assists too, not just killing blows.
9. For all classes - need new way to teleport to the entrance of the dungeon, without teleporting out and in again (this would be useful to hang in quests that are at the entrance, since teleporting out often puts you in combat, then you must kill mobs, by the time you're done - group has left dungeon and there's no way for you to teleport back in and hang in quests)