There has always been doubts harbored by the faithful, and always will.
But even when the faithful had doubts about their own faith in the eucharist, or the sacraments, they didn't doubt that the Church herself believed in them.
These new instructions, such as standing during the main portions of the mass, give people doubts about the Church's belief they didn't have before.
Agreed. It also tends to detract from the reverence due to Christ, IMO.