I think the reason it is difficult to take anything you say is that your sort of talking hypotheticals and not giving anything concrete.
Your saying 8 players in 5 positions is too much, because players like Sane and Sterling won't get enough games, you should show this if this is the case using simple maths. The first thing you have to ask yourself is how many full games (assuming 90 mins played per game) is enough in your opinion?
Using simple math: 8 players in 5 spots and with likely atleast 55 games next season that means on average each player gets (5/8)*55 = 34 games next season.
Using this process how many games on average should each player get that is deemed acceptable to you? (I'm actually curious).
7 players in 5 spots: (5/7)*55 = 39 games per player
6 players in 5 spots: (5/6)*55 = 46 games per player
and no depth means 55 games per player which is obviously a bad idea giving you no room for injuries.
Edit: Would like to add that I don't want Sanchez either, would much rather have Roberts come in and get atleast 25-30 games, with sterling and sane getting a bit more.