it really depends on the way a team plays. Of course a team will inevitably have its weakest or least important spot. But that area of the field where a player used to be assigned will be axed for one that's more important; that is how football develops.

There used to be a time when having a traditional no.10 was immensely important. Now that spot is axed in favour of wide players who are capable of cutting in and out and taking shots from outside the box. Cristiano Ronaldo's rise at Man Utd really sealed the dawn of the versatile attacker. You rarely get traditional no.10s who play at the top level these days. Even where a team on paper has a player in the no.10 spot, they are always interchanging with their wingers or deeper midfielders. Gone are the days of Rui Costa, Veron or even Kaka where they can play an only attacking role from only the central role.

Now on to why fullbacks are NOT a useless spot to plug in with an average player and call it a day. Remember when Real Madrid had to play with Arbeloa in RB? Yeah, those days were a nightmare for Madrid fans. He wasn't a horrible player, but a mediocre player in almost all aspects. An ok, quick runner, attacker, defender, crosser and passer. He was the perfect traditional full back; decent at plugging in spaces on the defense but contributes little on the attack. Other teams saw this chance and pounced on him. When Madrid attacked the lack of threat from Arbeloa's width meant they can triple up on Madrid's attackers. Compare this to Marcelo who constantly crosses, makes dangerous runs and links up really well with Ronaldo.

I can see your point on why you think fullbacks aren't too important. But consider this. When Pep was in his last season at Barcelona he played with Tello and Cuenca out at the widest positions and Alves/Alba were playing more as central midfielders. He played without full backs (back 3) and had 2 attackers playing the widest positions while the 2 known to be full backs were playing more centrally helping buildup the play.

Pep does this too at Bayern. He has Rafinha and Bernat as the widest players and Bayern's previous fullbacks at central midfield positions. Xabi Alonso, Boateng and Benatia as the back 3, Lahm Alaba and someone else as the midfield 3 and 4 up front. He plays really, without full backs, but the previous full back players are still in the team. What the heck?!

This goes back to my first point. When you see a position previously used as not that useful anymore because your way of playing is different, or your players can play better in a different system, you axe that position for a new one.

To put your previous closing statement into perspective; why are you even arguing about who's uglier when they're both clearly attractive and can bag you lots of money in model shoots for their own market?