I wouldn't buy a [EU] game that only allowed for six points of play. Part of the fun of EU3 is hitting the day button and watching events unfold differently, the ability to play as any faction at any time. Suggested start dates for EU3 being 1453, sure, that's fine. But don't force it on the player. That's just stupid. The gap between 1071 and 1453 is huge, and the stuff inside it is similarly huge. 1071 we don't even have a united Mongolia, The Byzantines are in decline but are still a huge fighting force. 1453 we have the Byzantine's gone for good and Austria, France, and England as growing powers. And the Mongolian Hordes have come and gone. There's nothing fun about that. It's just six scenarios of play instead of a whole world of possibilities. I think anyone opting for that is a bit crazy, no offense.
I think he was just talking about the times that titles should start and end:
1071-1453 for CK
1453-1789 for EU
1789-1821 for game about Revolutions and Napoleon
1821-1936 for Vicki
1936-1953 for HoI
Within that you'll have all your different periods.