Most times that I have watched him, I have seen him float. Acumen is nothing without effort especially when it comes to defensive hockey.
I have rarely seen that, to each his own, I just think this is something that is made up and people follow religiously that makes me laugh. Like when are you seeing this? The last time we played him he single handily thwarted a Datsyuk breakaway angling him perfectly and completing the play and that is something maybe 20 guys in the entire league can make.
He is often hard on the back-check, has a terrific defensive stick and is a very good short-handed player. Save for a very few instances on a team that had no defensive culture whatsoever I have always been extremely impressed with Semin's defense. Guess people can go harder, but for me this really is the NA media and many fans buying into a narrative on a player that is simply not true. I have rarely noticed it, flip around a lot on nights the Wings aren't on and will watch his team in particular because I am a big fan of how he plays in every zone.
He is a heck of a lot closer to Hossa than he is to Kovalev.
Also think this tag is generally interesting when thrown out there, certainly there are Europeans that have been almost all offense, but honestly not many. They generally are out of the NHL in a hurry if this is the case, which makes this stereotype a little funny. Most of the guys when you look around the league that play awful defense and actually make a career of it are from NA.