So many people want monks in their group o.O. I checked out their skills and it's not that great for buffs/debuffs.
1. the mantras have equivalent options on other characters. Barbs have bonus damage shouts, stuns, and can heal max hp instead of fixed heals. WD can do all of mantras but better .
2. It will be better to have more ranged than melee, specially squishy melee.
I would suggest 1 barb tank (cc,stuns,shouts), 1 wd (extra cc, extra tank, INSANE party buffs), and 2 wizards (nice party buffs, cc, and damage). I leave out the monk because I think it will be more dangerous trying to worry about another melee in range of big bad inferno packs. I leave out the DH because her only party benefit is "Marked for Death: Death Toll" and maybe "Sentry: Aid Station", but who's going to pick sentry?. Granted if the DH damage is through the roof, yo might want one for focus kills.
if you couple guiding light with heals on the monk plus the right mantra the monk can be amazing in groups. other skills like inner sanc will really help the ranged in your party. i would like to see a monk,wd,dh and throwing barb
24% from Overawe mantra of conviction.
16% for 15s everytime your healed by the monk... whos heal is on a 15 second cd.
10% on targets hit by Breaking Wave Crippling wave (one of the monks spamable spirit generators.) for 3s.
Thats an easy sustainable 50% more damage.
If the stars align with spirit generation it might be possible for a monk to also to spirit dump to keep up:
+24% more from Mantra of conviction activation (it does 48% for 3 seconds when you activate it... it has no cd so you could dump spirit to keep this up)
+12% extra damage taken by target under bleeding palm. (Although wording is odd on this so it might mean something else entirely.)
86% extra damage taken is insane. No other class matches that.
i was pointing out what great buffs it had for droppin since he wasn't seeing it... Wizards look like they will do insane single target dps and aoe dps... I wanna say every class in the game right now has some way of making a single target take ~20% more damage... so as for your question what in the world is a wizard bringing to the party:
he is bringing the DPS that makes all the monks +% damage taken skills worthwhile :P
Also this is about what will be the best 4 player make up, something that may be impossible to ultimately know, and most certainly wont really matter as blizzard is going to do their best to make sure that all classes remain viable, and with the all of the skill variations that each class has it's likely that any 4 player composition will work out.