Currently in the academy and on loan we have a "replacement" for every positional need except for a midfielder of Bernie's qualities.
LW-Edozie/Borges/Rogers
ST-Delap/Sodje
RW-Palmer/Kayky
LCM-McAtee/Hamilton/Bobb
CDM-Lavia/Charles
RCM-T Doyle?/Fiorini?/Robertson?
LB-JWE/Tarensi/Larios
LCB-Mbete/C Doyle
RCB-Burns/THB
RB-CJ/Couto
Excluding keeper, I think when considering only players 17 and over, who we know the most about anyways can't be arsed about super high potential 15 year olds, these are our current best players in the academy or on loan and the positions they can play... roughly. Obviously most of them can play in more than 1 position but this is to get an idea.
So far every position I believe has players who can potentially do the business as a replacement down the line.
But in the RCM position, or Bernie's position, we need a more defensive player (if the LCM is the more attacking spot which is what I am going with right now) for the balance. This is REALLY hard to find as I don't know if any youth player can offer what we need there in terms of ball control and stamina.
Outside of that though... I think we are pretty set for the next 10 years. If we can get 1 per spot to stay long term I'd be ecstatic (even if unlikely).