Messi is insanely good, probably the best player ever, but I DO wonder if his play-style stops Barca from having any other effective forwards.
Last season, Ronaldo-Higuain-Benzema scored 118 goals. Messi-Villa-Pedro (98 goals), Messi-Eto'o-Henry (100 goals), Messi-Ibrahimovic-Henry/Pedro (95 goals), and Messi-Alexis-Pedro (101 goals, though this was just an injury/form ravaged year for non-Messi Barca forwards) never did that. It seems that the front three in a Messi team pretty much are going to get ~100 goals in a season no matter what. And this isn't for lack of having other good forwards. Villa, Ibrahimovic, Eto'o, Henry, and even Pedro/Alexis to a less extent, are all world-class strikers.
However, especially since the 2009-2010 season when Messi moved to the center of the pitch, these world-class strikers have had a tough time producing. Henry only scored 4 goals in 32 appearances in 2009-2010. David Villa has only 35 goals in 82 appearance for Barca (0.427 goals an appearance), after scoring 128 goals in 212 matches for Valencia (0.601 goals an appearance). Ibrahimovic only scored 22 goals in 46 appearances for Barcelona (0.478 goals an appearance), but in the 2 years prior and 2+ seasons since, he has scored 117 goals in 174 matches (0.672 goals an appearance). Both Alexis and Pedro struggled with their form a lot last season. While there ARE other reasons contributing to these issues in every case, the fact remains that multiple world-class strikers have had a tough time producing alongside Messi. This is evident from watching them as much as it is from the numbers themselves.
This shouldn't be the case entirely. Yes, Messi takes up the center of the pitch and is the focal point, so he will take up a lot of the goalscoring chances. He also takes the penalties. HOWEVER, Messi also falls back into midfield a lot, leaving space for these strikers, and he is an excellent playmaker who can serve up assists to these guys. Meanwhile, the rest of the Barca team creates more overall chances than any other team any of those guys have played for. There are a lot of chances to go around.
I think in order to get the best out of Messi, you need to put him in the false nine role. However, the positions you put around false nines (wing attackers who cut in) are not positions that natural goalscorers are comfortable in. So you have three options:
1). Try to play Messi in the false nine with a striker in front of him. Barcelona tried this with Ibrahimovic and it seemed to crowd both men's space too much
2). Put natural strikers in the wing roles. Barcelona tried this with Villa and sort of with Henry. These guys found it tough to replicate their goalscoring exploits from the wings.
3). Put natural wing players in the wing roles. Barcelona tried this with Alexis. The problem is that natural wing players are not great goalscorers, so while Alexis did not score less than he had before he came to Barca, he didn't score as a Barcelona forward should.
There are no great options. I'm not saying Messi shouldn't be put in the false nine role. He produces there like no other player in history has produced. However, I think there IS a point to be made that Ronaldo scores so much while playing on the wing with productive strikers around him. When Messi played on the wings (prior to the 2009-2010 season), he scored a lot less, but the strikers around him (Eto'o and Henry) scored a ton as well (62 goals from Eto'o/Henry in the 2008-2009 season). Maybe those guys were just having great seasons that could be replicated even with Messi being in a false nine role, but I'm not sure given the evidence. Benzema and Higuain got 58 goals last season. Villa and Pedro got 45 in 2010-2011, Alexis and Pedro got 28 last year, Ibrahimovic and Pedro/Henry got 48 in 2009-2010. Seems the false nine role has made Messi MUCH better but at a fairly significant cost to the rest of the front three's effectiveness.