3 mages or 2 mages 1 priest for dps team

[nodoze]

I am a little tired but I think from an Alliance race standpoint the following are considered optimal races for the classes you are considering (though it should be noted that there are some ranking variations depending on who is doing the rankings):

-Priest: Dwarf (best by far for both PVE & PVP due to Fear Ward+Desperate Prayer+Stone Ward);
-Warrior: PVE: Human>Dwarf>NE>Gnome; PVP: Gnome>Dwarf>Human>NE;
-Paladin: PVE: Human>Dwarf; PVP: Dwarf>Human;
-Mage: PVE: Gnome; PVP:Gnome;

Note that it isn't difficult to get any of the Alliance races together. There are some short cuts documented in a few threads that make it pretty easy to get them all initially grouped (if needed I can help find that later after I get some rest)...

Personally I am planning on a 2 Paladin+2 Warrior+1 Druid Melee Cleave group for dungeon clears and from a WPVP min/max standpoint I have been thinking of doing 2 Dwarf Paladins, 2 Gnome Warriors, & a NE Druid (I want a WSG Druid flag runner & NE is the only alliance racial option). That being said my brother and I like the looks of humans & historically our mains have been Humans so we may end up doing at least 1 human paladin and at least 1 human Warrior.

If your group is going to do WPVP then I would definitely recommend you have 2 healers so 1 healer can help keep the other healer up if when gets focused. Personally I think 2 Paladins are the most survivable healing duo for WPVP.

With all the above in mind, for a WPVP focused group that would also being running dungeons, from the 2 group compositions you mentioned, I would respectfully recommend your group 2.0 adjusted slightly as follows:

-1 Warrior Gnome (PVE Tank, PVP DPS?);
-1 Paladin Dwarf (Heals);
-1 Priest Dwarf (PVE DPS, PVP at least off-Heal);
-2 Mages Gnomes (DPS);

That being said I am not sure if there is a single spec that makes for good shadow priest DPS and solid off-healing so you could instead go like your 2.5:

-1 Paladin Dwarf (PVE Tank, PVP Heals via single spec);
-1 Priest Dwarf (Heals);
-2 Mages Gnomes (DPS);
-1 Warrior Gnome (DPS);

Bottom line is that I am not sure the Warrior makes the most sense considering the rest of the group composition and would respectfully recommend you consider the following 2 options as well:

-1 Paladin Dwarf (PVE Tank, PVP Heals);
-1 Priest Dwarf (Heals);
-3 Mages Gnomes (DPS);

OR

-2 Paladin Dwarfs (both heal in PVP & 1 Tanks in PVE);
-3 Mages Gnomes (DPS);

Personally when multi-boxing I think the fewer the classes (or at least play-styles) the better and duo Paladins are the best healing duo in WPVP but I do see some merit to going with a Dwarven Priest (especially if you tend to get bored with fewer classes and play-styles). Another advantage of this last group is that they all start out together (though as I said it isn't that hard to get multi-race Alliance groups together due to short-cuts).