Yeah, they finished in 12th position, thus qualifying for the CL next season should be considered as progress. Chelsea have invested quite a lot of money on players, and i know that some people expect them to compete for the EPL title next season, but it isn't going to happen. Chelsea have players that are individually talented, but they need a coach that can get the best out of them as a team; Pochettino is a good coach, but he has to lower his expectations with the team for now, getting themselves back into the CL should be their priority.
If the next manager's main ambition is to return to the Champions League, then fighting for the league title by next season should also be on the agenda. It is true that Pochettino, the new Chelsea Coach, needs to lower their expectations, and I hope that doing so will not have any influence on the terms they agreed upon when contracting with him. It will not be an easy trip to get the team back to working together prosperously, but I believe Pochettino will do his best.
Actually, with Chelsea's current state, they don't have to be in a rush to aim for something high, especially when it's competing for the championship. For me, with the current condition of the team, even finishing in the top 4 positions is already a big achievement for them. Don't aim too big because that might put pressure on the squad, and if they can't control that pressure then they will be far from hopeless.