1)QBs not built for the spread, cannot outrun free defenders
2)WRs not there yet, and cannot get separation
2)Right tackle not good against a rush end, which means we will have serious issues containing the corner in the QB keep of the option. Plus we now have no FB to max protect when the end beats said tackle
3)brand new left tackle, possible same issues as #2, although we haven't seen him in real action
4)Guards much better at straight ahead blocking in power runs.
5)TE, with the exception for Arch, better suited for pro set
6)best asset are rbs, which are good in both systems, but really helps pro set
7)if any or all of above makes it so defenses are not scared of passing game they could keep players in the box, completely nullifying the spread