This post cannot promise to answer that question as it's really a who knows, but Redskins 360 did the math on at least one recent snapshot in time relevant to the above inquiry. He explains:
A question posed on a recent Redskins message board wondered what Seattle ran offensively against the Redskins in the teams' January playoff game, won by the Seahawks 35-14. This is obviously asked to start predicting what kind of formations Jim Zorn will use as the Redskins' coach.
He did the actual math, provided below, but let's quickly point out that a) Jim Zorn wasn't calling the plays in that game and b) I am sure his overall offensive philosophy is subject to change given varying circumstances, including his own and opponent's personnel, down and distance, scoreboard, etc. Redskins 360 counts:
54 total snaps of which the breakdown is as follows:
14 WR and 1RB set (~26%)
10 3WR and 2RB sets (~18%)
17 3WR and 1 RB sets (~31%)
8 2WR and 2 RB sets (~15%)
4 1WR and 2RB sets (~7%)
1 5WR set (~2%)
As I stated above, this is a tiny snapshot -- one game -- of a different team's offensive sets, with different players, under a particular set of circumstances. As Ryan O'Halloran points out, the presence of at least one great TE in Cooley plus another high potential guy in Fred Davis would alter the above substantially, since 3WR and 2RB sets, for instance, wouldn't provide any space for a TE (unless Cooley or Davis is lined up wide). Only the 1WR 2RB set provides for dual TEs, and the article notes that Seattle fell on that only after they managed a solid lead.
But I don't want to wait for a solid lead to see my potent two TE, Cooley and Davis and Moss and Portis and Sellers set, I want to run it noooooooooooow.
Here's the problem for the other poor bastard... Davis and Cooley and Sellers and Portis together makes for a fearsome running group that cannot be ignored. Cooley and Davis in that set, though, along with Moss, also makes for a fearsome passing group that cannot be ignored (pretty good pass protection, too, ignoring whatever nonsense [hat tip to Fanhouse] Mike Lombardi is talking about Clinton Portis in pass protection -- name me a RB that's better). And so that guy gets to make a business decision about who and how he's going to deal with a multi-threat formation.
Then again... With both Kelly and Thomas on the team now, I kind of like a 4 WR set, which would've been hazardous when it was just Moss and ARE and then James Thrash + whoever? Brandon Lloyd?
Do I know that Kelly and Thomas are necessarily better than Thrash and Lloyd? Not really. I know they're taller at least. And when it comes to WR combos, I'll take the unknown duo with potential over the known meh group. (Note: I like James Thrash.)
And while we're on the subject of our newest Redskin WRs, and Mike Lombardi, he makes an inadvertent point about the future of another Redskin:
Zorn will try change the "Redskin Joe Gibbs" offense into his version of the west coast offense. That will be a slight challenge and there will be some adjustment time for the players as well as the coaches. Some of the assets he has on offense, like Santana Moss and Clinton Portis are not best highlighted in the west coast offense. Moss is an explosive player, who is best running over routes and deep comebacks, not slants and snags. When the Jets ran the west coast with Paul Hackett, Moss was the change of pace wide receiver he was used for specific routes as Laveranues Coles was the number one wide receiver.
I don't want to give too much credence to all this; I think Santana Moss is at least capable of exceeding in whatever system he plays under, since he can be and has been a special kind of player. There is no offensive system that is not,at least on occasion, better off with a guy who can outrun the entire opponent's secondary with unrivaled adjustment-to-the-ball-while-it-is-in-the-air. I think Moss is fine, will have a place in this offense.
What about Antwaan Randle El, though? He's very nearly the same build as Santana Moss, is a great YAC guy with good speed. Whatever criticisms can be leveled towards Moss relating to his place in a WC system apply equally to ARE. I hate to say this because ARE is a special kind of player in his own right, but, isn't he just a Moss-lite? They aren't indistinguishable, but share a skill set and Moss is simply the more productive WR over the course of their careers. I wouldn't want Moss returning punts necessarily, or throwing WR passes, but if I had to choose just one starting WR I'd take Santana over Antwaan. Am I wrong about that?
And if it's the case that Moss (and by comparison ARE) have skill sets and size disadvantages that don't lend themselves to the West Coast offense, is it possible that Randle El may not finish the year at the #2 WR?
That's the new poll question, enjoy.
Psssst: I voted for 3rd WR behind either Kelly or Thomas but not both.