Some facts.......
FMS systems do have buffet boundary protection, low speed and high speed, generally 1.2 to 1.3 g depending on the manufacturer and aircraft type.
They also do have temperature prediction models.
The max power and min rate of climb models vary slightly and may in some cases be configurable in the AMI file by the airline.
I am not a proponent of blind faith in the FMS predictions. The FMS is a low accuracy tool that hs such limited data sets that true optimum decision making is not possible.
Today's flight planning systems do a far better job than an FMS.
I would speculate that the future will see the use of tablets and EFB products as pilot decision making tools and the FMS being a tool to allow the Autoflight system to strategically manage the vertical and lateral flight profiles.