Not sure wether it should be posted here, but while i have seen a few discussions on synergies i haven't found a complete listing yet. And since it's about facts on not opinions, i thought it'd be better here.
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Seeing all the changes to skills and talents that will be coming with wotlk, i thought it would be usefull as a raid leader to have a good overview of what any spec can bring to the group without having to go through several talents pages on the usual websites. Thus i made myself an excel spreadsheet listing all skill/talents that i counted as synergies (buffs to single/party/raid and debuffs helping mitigation against or increasing damage to mobs). As it isn't possible to present all effects in a simple manner, this spreadsheet won't replace knowledge of each skill and talent from each class. It's purpose is simply to help me and other raid leaders to get to know them, and providing a tool to check up on things rapidly.
It took me a certain time to write it and as such it might lack a bit of coherency in the denomination/classifications used, though i did do several passes over it afterwards to make it better. I tried to use several classifications (as objectively as i could) to make things clear and easy to filter in several ways without bloating it too much.

It's supposed to be complete with regards to the current beta state, though i might have missed things/parameters or misunderstood stuff. As such it's open to correction (and changes to beta will have to be integrated too).

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What it looks like :

Dowload links for the excel sheets :

Raid Synergies list 0.52
Raid Synergies list 0.51
Raid Synergies list 0.50

Nice organization of all pertinent buffs / debuffs.

I did notice you were missing the druid's Feral Aggression though (for upto 40% increased AP reduction on Demoralizing Roar).

Edit: Sunder Armor seems to also be missing.

Unsure the example reflect the current content of the file, don't have excel viewer installed on this pc, but the DK stuff is wrong, auras aren't linked to presence anymore, so they only require the talent, and acclimatation doesn't require any specific presence to work either.

Edit: Also linking imageshack in EJ will probably kill it by tomorrow. Just saying ^^.

Abom's Might is 10% attack power and is raid-wide (sharing buff with Enh Shaman).

The Moonkin and Feral Auras are planned to be raid-wide (not sure if that was patched in yet).

I think you'll have to reevaluate your sheet according to this: WoW Forums -> Changes to Debuffs, Buffs, and Raid Stacking

Edit: too late

Well, the list is still a rough draft, but we can start coming up with the minimum number of characters needed to cover every buff. If you want this automatically solved you could model it as a network-flow problem (shaman totems might push it into integer programming), but I think it can be solved by inspection.

I can get it down to 8: moonkin, disc priest, arms warrior, ret pally (with BoK), mage, shaman (dropping Wrath of Air, not windfury), fury warrior, frost DK. That misses out on spell slows and RAP buff, but covers every other category, and if the +dmg effect on IDS is as small as it is now that may be the smallest one of all the applicable talents. When we find out what other class can cover Blood Frenzy that may ease up the list a bit, by allowing a feral druid to cover all the warrior buffs.

Currently I think ferals and warriors overlap too much (-AP, +crit, +bleed, -haste) and affliction warlocks are rather underpowered as a support class. We'll see if that's acceptable to the developers after some amount of testing.

Also, who belongs to Horn of Winter? I do not recall seeing such an ability anywhere.

While it's true the classes overlap, the real-world specs mean a warrior is only going to provide two of those at most.

-haste: It's serious DPS loss for a dps warrior to maintain thunderclap and it's resisted like a spell vs a feral druid just getting it for free when they use mangle.

+crit: Only for deep fury warriors.

+bleed: Only for deep arms warriors.

-ap: Yeah, every warrior can do this. No prot warrior will ever have the talented version.

Unless something changes with Feral Aggression between now and the expansion, no druid will have the talented version either. The mentioned re-evaluation of the feral tree hasn't happened yet, so anything's possible however.

An arms warrior may be in Battle Stance full-time because of the overpower-on-rend-tick talent. Merging melee and spell hit will clear up the resist issue. The overriding concern will probably be threat, followed by rage and GCDs. I wouldn't expect a fury warrior to be able to pick it up.
And while that's good for the druid that they can cover those, it's not as good for the DPS warriors. I hope their DPS is as off-the-hook as their talents look right now, because if their tanking and utility is strictly worse than kitty-feral they're a wee bit hosed. The point is that different classes bring different things to the raid, not that some simply bring less than others without compensation. As it stand the only thing of note a warrior would bring over a feral is Sunder, which is replaceable by EA albeit at a non-trivial cost.
(Note: I'm not saying zomg nerf ferals buff wars, I'm saying these are the considerations that I would like voiced and taken into account when blizzard moves from their rough draft to their next polish pass)

re Imageshack : didn't find anything on it in the rules and i thought it'd be preferable to give people an idea of what it'd look like without forcing them to open the file (and without killing my webspace's bandwith). If there's any alternative site better suited for here (or if i should just remove it), it's not really an essential part of the post.

Hadn't seen that one yet, thanks. It will help to categorize things now that we have an official list, I'll probably wait to change some of the effect modifications they gave in this new list because it seems a number of them haven't been published yet (probably form their internal build). Same for Horn of Winter.
I'll probably collapse some of them though (buffs/debuffs, flat/multipliers). Moonkin and Feral auras aren't raid wide yet.

I'll try to add what i've missed during the day at work and rework the categorisation according to the list.

Don't hesitate to tinker with it and add more tools, i'll have to admit that i'm not motivated/knowledgeable enough with Excel/programming to work on such things.