Most of the out-of-contract players who started yesterday probably should get another year if acceptable to them.
The key is to then move the rest of the squad on and improve upon the current fringe players so the starters yesterday become backup options. Our loan signings in the early part of the season actually weakened the first team vs improving it whereas Beadle, Poveda & Ugbo massively improved things.
We have a huge raft of out-of-contract squad players who will be moved on (Bakinson, Wilks, Gregory etc) and a bunch of loans who won't be coming back (Hendrick, Fletcher, Diaby etc) as well as some who are just surplus to requirements (James etc). If you can improve on these who are essential bib fillers in training with first-teamers then you slowly improve the squad while keeping the nucleus of a team.
The problem with last summer was we tried to change too much and ended up defaulting back to the guys who got us promotion with a couple of quality loan additions.