I am running DK, 4x Shaman and I haven't noted a significant change.

If anything, I have fewer mana issues particularly on boss fights, but this is clearly due more to improvements in gear than due to a change in game design.

I hate drinks hotkeyed, and I'll drink when my team is less than 35% mana. Usually happens every three 3-4 mob pulls.

To me, it seems that healing sucks more mana than anything else my group does. I do tend to not cast CL when I am down to 2 mobs and just spam LB at that point. Also, I hardly ever use TS mid-fight unless the DK goes down. I will use it on occasion when running to get set up for the next pull in order to sped mana regen.

I know that this is not "optimal" from an efficiency standpoint, but it works for me and my playstyle.