Some of the org ownership/management/coaching staff most certainly are, yes. Players don't control the rosters, though. Even though it's fair to say that they'll be granted some creative space to make suggestions or make requests of specific players for their leadership in their orgs to consider, though. IGL's would have the biggest influence, but most just make the best they can out of the rosters they end up with.
I do think that players you're building rosters around should have a little more control over the makeup of the team, though. And in some cases they probably are given a little bit of control, but that also depends on the org.