I am so glad you asked this question, as many other players are asking this too! Before you start reading, grab a cup of coffee or some popcorn. This is gonna be a long response....
I am a level 52/41 Warden/Warrior on Reni. I can't tell you very much about gear and instances (at the moment, I can't do Kalin's Shrine yet), but for the majority of your questions, I have a good amount of booksmarts to answer them thoroughly.
Before asking any questions, the first thing to do is to forget about the Warden combos and their Elite Skills for the moment and ask the question: "What is the Warden's purpose as a primary class?" That's an easy question; we are a DPS class like the Rouge, Scout, and Warrior.
With that in mind, you can easily predict what your role is going to be in a party if you're NOT a Warden/Warrior (I'll explain the Wrd/W's role later). You'll be doing DPS.
To answer your question, "Which Warden combo is better: the Wrd/S or the Wrd/R," I would say that they are locked in a pretty tight competition against each other for the title of having the highest physical DPS out of the Warden combos, and they've been that way for a long time. According to players like Xeph (aka "earthenleaf" on the Warden forums), the Wrd/R is the best single-target DPS Warden. But also keep in mind that the Wrd/S has a
ranged pet (which should be pretty handy in SW) and both its pet and the Wrd/S can put up a very good fight, so it's still a win/win situation no matter which way you go.
Now it's time to discuss the Warden/Warrior:
Because of the changes to the Wrd/W's elite skills, we now have a totally different role for us and there are many ways that you can set up the Warden/Warrior for tanking/off-tanking (which I will touch on later). The fact that Runewaker gave us some aggro skills and the ability to wear plate armor screams loudly of your new role as a tanking Warden, but you still have the choice to go either off-tanking or DPS if you wish (I will also touch on that later). For this topic, I am treating the Wrd/W as a tank/off-tank. If you're a Wrd/W, I advise you take advantage of your new Elite Skills and go with the tanking route and drop the role of DPS. I will learn much more when I can eventually get into instances like HoS, HotO, Grafu's Castle, and stuff like that.
In your post, you said: "the thing we dont have with as a warrden is a crowd contro abbility like the knights and i would like to know if that plays a big role? or is will attack with the pulse mastery buff enough?"
That is slightly incorrect. We do in fact have a few Crowd Control skills at the Wrd/W's disposal. Remember: we have a root called "Movement Restriction." Depending on your skill's level, it can hold the target long enough for you to re-summon your pet if you need to and it also does good damage after the effect ends. We have
two physical dps AoE's: "Frantic Briar," and "Whirlwind" from the Warrior's general skills. I think the amount of aggro you can pull with those 2 skills depends on how well you're geared, but I'm not totally sure. Another Crowd Control skill is "Banish." What it does is that it makes the target unable to attack or receive damage for a duration of time. Banish can be handy in certain situations as it can completely take a mob out of the fight for 5 seconds (if Banish is at level 1). You can also use "Cross Chop" as a ranged-pull to pull a mob off of your healer. Not only that, but you must also never forget that you're a WARDEN.

Lol. We were meant for taking on mutiple targets! >

The Spirit of the Oak has been the Wrd/W's signature pet, since it is our tanking pet. It has higher stamina and physical defense than all the other pets. Also, the SotO's pet skill "Punch" is an aggro skill. You can use that to your advantage when your party is in combat by keeping the SotO focused on your primary target while you take care of the mobs attacking your weaker allies. All of those skills
do play a big role in a fight; it just depends on your strategy and how you will use them. So that answers your Crowd Control questions.
As far as whether Pulse Mastery and Will Attack are enough, I do not have the Talent Points to level up both Beast Chop and Pulse Mastery and I have not obtained my level 45/45 elites yet. Also, I'm still waiting on the Advanced Skill Reset stone that Frogster or Runewaker is going to send us to reset our TP. So I can't really know for sure since I don't have the instance knowledge to test the aggro limits of Double Chop, Beast Chop, Pulse Mastery, and Will Attack yet.
To answer your question about going dps or tanking with the Wrd/W, I have a few things to day about it. If you look at our elite skills, you can see that they do very nice physical dps damage---especially when you look at Pulse Mastery when it's maxed out (the dps percentage is like 552.2%).
I.)
For high burst dps damage:
You have these attack skills at your disposal:
Power of the Wood Spirit (
Edit: I replaced Charged Chop with POTWS due to obvious reasons

-- 8/19/2011), Slash, Double Chop, Beast Chop, Pulse Mastery, and Will Attack. In my opinion, I wouldn't max out Power of the Wood Spirit but keep it at a high level to help out leveling your Warrior's side. Aslo, you
and your pet also have attack buffs you can use to increase your physical attack power: Savage Power, Berserk, Energy Absorb, and Explosion of Power (for your pet). You'll want to use chain armor, a 2h sword (Annelia's Blade when you have the gold for one), and the SotO's buff and the Oak Walker as your primary pet.
II.)
For tanking:
***NOTE: Updated as of (8/19/2011)***
This is where things get pretty flexible as far as your weapon set up, and your Pet Buff and Pet Choice go. You'll be using plate armor, so that's a given. I have some ideas on how you can go for tanking including tips on skill strategies.
NOTE: Use skills that only increase your survival and physical defense (like Immortal Power, Defensive Formation, Damage Transfer, Elven Amulet, and Coat of Arms), and use Explosion of Power to increase your SotO's attack damage (and aggro?).
1.)
Independent Tanking Style: Use a 2h weapon (try to get it to Tier 8 or 10, plus it high enough, and put a Hatred VIII rune on it (also get the rune that raises your physical attack speed). Use the SotO's buff and the Nature Crystal as your primary pet. This is the truly the only practical way of tanking as a Warden/Warrior, since the NC gives you a party buff that allows you to take 10% of your maximum health in damage. This will be the most popular style of tanking.
2.)
Off-Tanking Style: Use a 2h axe or sword. Use the Oak Walker's buff and the Spirit of the Oak as your primary pet.
3.)
Tank's "Damage Assistant" Style: Use either a 2h sword. Use the SotO's buff and the Oak Walker as your primary pet. **Use skills that increase your own physical defence when needed (like Defensive Formation and Elven Amulet) and skills that increase your Oak Walker's physical attack (like Explosion of Power).**
----> Until the Oak Walker's bug is fixed, this tanking style won't be available. I'd advise not using Damage Transfer so that you don't hurt your Oak Walker.
***IMPORTANT: I've heard reports from other Wrd/W's that using Defensive Formation [B]decreases your aggro, so be careful out there!***[/B]
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About the Wrd/W being a "better tank" than the Knight and the coming Knight patch:
I believe that Knights will always be the real tanks for RoM. There's no escaping that. Especially since they're going to get their class fixed some time in the future. If you read the 4.0.1 Patch Notes, you can tell that the Warden/Warrior was intended to be an "off-tank," like a 2nd place tank (I think the Wrd/W and the W/K are now in competition for 2nd place). But I have indeed heard reports and arguments from a higher leveled Wrd/W that the Wrd/W
can tank better than the Knight at the moment (but there are too few end-game Wrd/W's to prove that to the rest of the player community). We certainly do higher physical dps damage than the Knight, we've got our pets to help us out, we have better physical defense skills than the rest of the Warden combos, AND our pets now have better chance of survival---pets now get a 100% AoE damage reduction, instead of an 80% reduction like it was in Chapter 3!!!

The underlying question here is: "
CAN the Warden/Warrior tank and tank well?" I certainly hope so.
Wow. That took a while to type. <

I hope that answers all of your questions! The rest of the Wardens with high leveled instance experience can fill in the holes that I left out.