His future pathway is just like any other talented youngster, go on loan and show your talents and if you are good enough, you may come back into the first team.
If Paez was expecting to walk into the Chelsea first team, then he was either sold the wrong message or he's got a massive ego and he'll probably be running off to a Spanish/Portuguese club in a season or two.
As for goalkeeper, I don't see any stockpiling of talent, it was clear that Petrovic wouldn't be the #1 this season and thats why they mutually agreed to keep him out of the CWC squad. The weird part is, no-one has really come in for him, even though he did relatively well in Ligue 1 last season.
Maignan was our only shot at fixing the GK situation and at least getting a good keeper in for 2-3 seasons and in the meantime Penders would develop on loan with a view to first team football. Now we're stuck with Sanchez for this season.