As to the fit, no that isn't right. A properly fitted door will open
and close just as easily right after installation as it will years
later (assuming the foundation isn't moving around!:~) If it is hard
to turn the knob, it will continue to be difficult. Either the knob
isn't aligned correctly in the door or the striker plate isn't aligned
with the assembly. Either way it is aminor matter of adjustment to fix
the problem and one the installer shouldn't have left you with.

Or there's weather-stripping on the doorstops that the installer
expects to crush down over a few weeks.