Limited role?
Mintex, during his 3 seasons at Barca, he practically played every game. Barca fans like me will always remember him fondly (especially for his great goal in the clasico) an his hardwork at all times, but all of us also saw his lack of quality in terms of finishing chances - especially when compared to Messi or Villa or Pedro during that period.
Yes sure, he has a bigger role at Arsenal but he was never a bit part player at Barca. You can't be just passing to Messi and still get 20 La Liga goals which he got lseason before last. Infact during that year Messi was out for 2 months so Barca completely depended on Alexis and Neymar to score goals. He wore the famous #9 as well. Not so limited then.
I can also say that it is amusing that Arsenal fans can assess his quality after just one (although great) season. Plenty of people have had a good season and then not so good which is also what happened to him in Barcelona btw.
Perhaps you meant the freedom to roam and dictate play - on the pitch? Well he mostly played on one side of the front 3 or as a central striker but Messi obviously had complete freedom of movement, but then you cannot have everybody with the same tactical role can you?
As for Suarez, well no way can I condone his behaviour in the past but he has been very good in the red and blue shirt, and do you really believe that Arsenal would not have signed him if they could have? Just for upholding ethics and sportsmanship?