flobaba Firstly, I agree that some of it is speculative on my part and you could be right about what Arteta's thinking long term.
But the reason I feel that what we see in terms of Saka and Martinelli's role isn't set in stone is because of glimpses we've had this season.
Martinelli, for example, has gradually shifted more centrally as the season has gone on. We played him wide in the first half (particularly when Nketiah was playing) but in recent months, particularly since Trossard was in the team, he's become more narrow even if he starts the game out wide (e.g. see his goal at Anfield or his goal vs Everton (H))
Using Squawka and checking for duels, interceptions etc you can see that Martinelli has done less than Saka and although I can't split the data by month, I'm willing to bet that they were probably both evenly matched pre-March as both are hard working players by nature but Martinelli's role shifted because he's shown signs of being more clinical.
The other reason I feel like Arteta would be open to a similar role for Saka is purely because of how Sane and Sterling were managed at City. They had a similar degree of flexibility in their role and by all accounts Arteta was responsible in their development.
Generally speaking, I think it would be a waste if Saka continues to play in a more withdrawn role. He should be spending the majority of his time in the final third and preferably as close to the box as possible.