Yet he's played there for two seasons in a successful team, and is consistently one of our best players. What he lacks in crossing he makes up for in overlapping and underlapping runs, determination, and he has a nice finish when given the opportunity. Quite simply he is a more than good RWB, and has shown it for some time. It's easy to see that from the games he's missed. Of course he's not a natural, and people often prefer attacking RWBs, but that's a different issue.
In a league that has lack of quality wide players, defensive ineptness shown by most teams more often than not, where defenders can't fulfill basic defensive responsibilities he was very good, but the real difference was seen in European games. You can't compensate lack of attacking talent with hard work and determination. With an additional player on the flank, be it even Marchisio, we would see less of Vidal or Pogba going wide to provide him support, simply they could pose more threat in the central area.
That's because you're assuming the two positions are much the same, which they aren't. He's not a defender, yet will be expected to defend deep against direct attackers, hold an offside trap, and cover the back post from crosses in. Here he has to play as the last line of defence. I'm confident he'll do ok there, but we are nullifying the guy even further. He can't drive forward and play as much of his natural one touch game from the left. He won't have as many opportunities to dribble directly at players, and will be expected to cross more on the overlap. That is the weakest point of his game. We're already taking him out of his comfort zone by asking him to play as a wide midfielder asked to defend, let alone as a wide defender.
I'm certainly not assuming that and in the previous part regarding Licht it is evident. Asamoah put in wonderful performance in Madrid, but I had mixed feelings for the one in Turin. Very few players wouldn't face difficulties when facing player of Bale's caliber, but he could handle the likes of Florenzi or Gervinho, of that I'm confident. You're forgetting that both FBs in a 4 men backline don't have identical responsibilities, while the one is more offensively orientated, making overlapping runs and providing crosses, the other one stays back and forms in most cases 3 men backline.
Regardless of formation we can beat this Roma side, position of players is at times irrelevant, but their responsibilities are what could make a difference. It all comes to having a well balanced side, players capable of creating chances and the ones simply better at defensive tasks.