Looking back to the last Armies in 5th post for Space Wolves we identified their main style of play - aggressive with fire support. This is feasible in a large part to the efficiency and effectiveness of units like Long Fangs and Grey Hunters combined with Space Marine transports (Rhinos and Razorbacks). What's important to distinguish here is not that Space Wolves are gung-ho, charge forward and chop crap up. Even with excellent combat units such as Thunderwolf Cavalry + mounts isn't always going to lead to success. There's no denying Space Wolves across the board are a more aggressive army than Vanilla Marines or Imperial Guard but they actually work better as a sort of 'counter-assault' force.
This is due to a couple of mechanics within the Space Wolves codex. The first is obviously the counter-attack special rule which allows Space Wolves to get a bonus attack when charged on a passed leadership test (another reason Wolf Guard are so important in Grey Hunter squads). This really helps Grey Hunters be a much better combat force. They certainly aren't amazing but are very solid with counter-attack when being charged. Getting a charging bonus when being charged combined with the ability to double-tap gives you maximum damage potential against units. That being said, the brilliance of this ability is not always in the capacity to both double-tap and have three attacks base in combat but the choice to choose.
Consider the predicament your opponent has. If they play defensively the Grey Hunters can dominate midfield, rapid-fire with bolters and ultimately finish up units with pistols + assaulting. If they play aggressively the Space Wolves player has a lot of options in boltering + getting assaulted or being aggressive and pistoling + assaulting. Either way, the Grey Hunters are doing well and depending upon your army make-up or specific units in question, will dictate how the Space Wolves player acts. For example, the Space Wolves player is going to look to deny units with Furious Charge the assault which can blunt their effectiveness quite a bit (hey Orks and Blood Angels). Whilst double-tapping + counter-attack might net more damage, using the flexibility of the Grey Hunters squad gives the Space Wolves player more tabletop control. Very few armies have this sort of flexibility in their core Troop choice, let alone across their whole army.
If we further apply this to the whole army, you can get unique benefits elsewhere. After finishing units off in assault, the assaulting units can often be left high and dry. Whilst counter-attack doesn't really hep units stave off shooting, any remains of the unit which do get assaulted are that much more potent. Other midfield units such as storm bolter Wolf Guard can use the same tactics as the Grey Hunters to put your opponent in a difficult position and give yourself a lot of tactical flexibility. Even backfield units like Long Fangs are harder to take out with weak outflanking/deepstriking units and whilst they won't kick rear end in combat, they will be more difficult to take down.
What exemplifies this counter-assault notion across the Space Wolves army is their main assault units such as Thunderwolf Cavalry. There is no denying TWC based units are very good and tough in combat but there is a distinct lack of a cost-efficient super unit for Space Wolves. There is no quick and easy unit like Paladins or TH/SS Terminators that you can plug into most combat situations and be secure in the knowledge of the outcome. Whilst units like Wolf Lords, TWC, Lone Wolves, etc. are all very effective as combat units, they are often much better as beater units or clean-up crews. You can certainly tool them out to be the ultimate unit in terms of offensive and defensive abilities but this costs a lot. The units rather rely upon their MEQ statline and token storm shields to pull them through the day and this makes them excellent units within the Space Wolves army to extend the combat threat.
This takes a lot of the burden off Grey Hunters as they no longer have to do everything. They are still an excellent unit which does pose quite a few problems for your opponent but if you back these up with more capable combat units (which often have greater threat ranges) engaging the Space Wolves midfield is a much more daunting process. Managing these threat ranges and different units in terms of how you use Space Wolves aggression is key to their success. Play too aggressively and try to get into assault more often than not and you might be better with a Blood Angels list whilst play too passively and look to shoot more often than not and a Grey Knights or Vanilla Marines list might be the better option.
Back this all up again with cheap and effective ranged shooting such as Razorbacks and Long Fangs and the Space Wolves army as a whole is more capable of sitting in midfield and managing threat ranges to ensure maximum damage and have high counter-assault capabilities. If there was less or no backfield firepower coming downfield to help suppress/destroy the opponent the Space Wolves would be forced to be more aggressive as the burden of damage is placed completely on these elements. This would ultimately lose out on the flexibility these unit combinations have and thus having access to such firepower is important to allow these units to operate at peak efficiency.
