You're being way too limited in understanding their roles on the field. What you're talking about is the old fashioned system put on paper. You must have noticed by now how the game has changed.
It has been for decades this way and i wont change my mind because of Pep, i dont even consider hum a coach, unless he prooves himself with inferior players.Conte or anyone else trying to imitate those tactics are destined to fail, because Pep;s players are so much better, that can deliver anyways...
Except me, 90% of the Italian coaches still share the same concepts.
And at any case, the need to create and score a goal are still there, regardless of the tactical choices and we must not lack the tools for it. I dont want to see us implying the usual old tactics, but i want us to have the natural options open.
Anyway, Pepe was never called a SS, lets not put words into peoples mouths. He was called an attacking player and part of the front three in Conte's 4-3-3 system, which isn't a 4-5-1 as you call it since both Pepe and especially Vucinic are almost never in the same line with the central midfielders. Pepe is a forward in Conte's system simply because he plays there. And yes, he's supporting the central forward up front so technically you can call him a SS, but in the actual understanding of the SS role, he definitely isn't one.
They are never at Matris line either, so that goes both ways, but just like i said they spend most of their time closer to the midfield, rather than the opposition box.
Pepe being a winger tends to start deeper, Vucinic being a forward tends to penetrate deeper.
They cant have the same roles, because they are different kinds of players and this causes an asymmetry.
Call them what you want, but they are different and it doesnt matter what we put them to do, their footballistic characteristics will prevail on the fields they are good at, thus resulting at not being as good on a specific asked role and the inevitable loss of their loss of optimal performance, according to their potential, because of that. (ex Pepe cant score what most of the SSs would and Vucinic cant defend as most of the wingers could)
This is a natural result for every player, being played out of position. Sometimes, those small individual compromises work well for the common good, as its our case, but if you have quite the dedicated tool for the right job, you can optimize the performance.
IMO wingers fielded as SSs in a 4-3-3 will cause finishing issues.
I ve always believed that and i see it happening every time we play... so this not just my impression and according to my logic the finishing will improve if you replace the winger with a SS who is able to score and Quaqs is just that!
As for Quag and the other forwards you mentioned....yes, he's playing the same role as them, just that he wasn't blessed with the goalscoring instinct as they are. He always goes for the goal and rarely, almost never, for the pass. He can't do much playmaking either and he definitely can't function from the wing and cut inside. His instinc will push him to the center of the box and we will lose width since he won't go back to the wing when needed. He has more characteristics of a CF than SS. Naturally, he can play in a forward duo with a less mobile and taller striker, but again he will play as a typical CF there.
Quaqs adapts to the teams needs because he is versatile, so does DP, DP can play as a straight CF if he is paired with a SS like Quaqs and a SS if he is paired with a CF like Treze.
Such gifted players maximize our performances and can fit into many schemes/roles.
This is why imo Quaq>Vucinic, Quaq can both create/support and score, but Vucinic is a terrible finisher.
He must be always paired with a finisher.
So i agree that Quaq can replace Matri but i disagree that he cant be paired with him.
You just underestimate his supporting capabilities.
And serving isnt everything, off the ball runs and creating havoc to make space elsewhere is.
To make it shorter: Yes, in our formation Quagliarella is a direct replacement for Matri and he'll do the best if he plays instead of Matri while he'll struggle if he plays instead of Vucinic and Pepe. He can play together with Matri of course, but to get the best out of him there, you'll need to take out one of the CMs, take Vucinic out and change the formation, by adding a winger.
To make it clear for you, these are the 10 goals he scored for Juve. Maybe they'll tell you more.
01. Sampdoria 4-4-2 (Quag-Del Piero)
02. Udinese 4-4-2 (Quag-Del Piero)
03. Lecce 4-4-2 (Quag-Amauri)
04. Milan 4-4-2 (Quag-Del Piero)
05. Cesena 4-4-2 (Quag-Del Piero)
06. Brescia 4-4-2 (Quag-Del Piero)
07. Catania 4-4-2 (Quag-Iaquinta)
08. Catania 4-4-2 (Quag-Iaquinta)
09. Chievo 4-4-2 (Quag-Iaquinta)
10. Novara 4-3-3 (Esti-Quag-Pepe)
In these goals we have 2 versatile forwards combing and doing great things, the aim for both is to score, why? because they both can and they help each other by creating a multidimensional front.
If one cannot score, like the goal waster Vucinic, he can only provide support and thus only by judged for that. BTW how many assist Vucinic had so far?
So as Vucinic, DP, Giacche and Quaqs can all work with a CF like Matri (who is also, imo versatile enough himself, as he can create and support, at least as good as he scores)
They can all co-exist and as they are versatile enough to adapt to our needs and focus were we need them, they could maximize their performance.
Ex Vucinic avoid tryind to score and focus at what he does best.
Matri mostly have an eye to score, but share that role with Quaq, so that it will be harder for the opposition to stop them simultaneously. And finally Quaqs, offering in the box what Pepe is trying hard but mostly cant offer.
Imagine having Quaqs taking all those shots Pepe wastes!
PS: I m telling you Allen, such a 4-3-3 would be an overkill and after they develop a teamwork, unstoppable.
It would also boost our need for another CF (Boriello) and more CMs (Pizarro, Montolivo) still offer more playing chances for DP and make Krasic and Elia totally unneeded.
Just make an effort to envision it!