Not really, as it is relative to era. This argument crops up on NBA forums all the time too, although in the 70's, the NBA it is probably the weakest due to expansion. I would say that in the 80's you start seeing the average player being a bit better, especially filling out rosters. Average player size on the lines certainly started to creep up. But that also goes across the league, relative to speak.
Stars will be stars in any era. QB's like Roger, Johnny U., Bart Starr would fit in well at QB today, as would Troy.