After playing for about 3 hours or so I'm fairly impressed with the strides made from the previous versions. It seems like we have a solid base that just needs some tweaks here and there. I'm sure I missed some of the other issues, but for my playtime these were the top ones:
1) Crosshair Size. The crosshair size is WAAAY to big for people who use 'fairly' large monitors like myself. I have a 24' monitor and no matter what resolution/aspect ratio I set it at it was still too big. Here's what it looks like:
It gets even worse when spraying:
I think you either need to give the cl_crosshairscale command back or use some other method to reduce it's size.
2) Spectating jitterness. When spec'ing another player it feels like there is a lot of lag and skips, almost as if their rates are very low. This happened on every person I spec'd.
3) Damage done. I'd like to see in console the damage i've done to other players, i'm not sure if servers can add a plugin for this or not. Either way I think it should be part of the default game.
4) HP/Dead Scoreboard. It's hard to tell sometimes who's alive and dead because both the DEAD and HP text are the same color. I would suggest changing the colors.
5) Awp Quickswitch Delay. This is really a personal opinion rather than a game issue; but I don't like the awp delay when quickswitching. This wasn't always a part of 1.6, it was added in a steam update after 1.6 was released. Maybe people prefer it as a balance issue but I'd like to see it removed and have the awp act like it did in the 1.5 version and below, not sure if i'm in the minority on this or not. Either way it's not a game-breaking issue.
Tha'ts all I can think of at this point.