Since we added a few things for the historical mode into the second pre-beta version I can talk about it a bit:
First of all, the modern game has absolute priority for us in version 1. That said, right now I would say that changes are good to have at least a basic form of historical play.
As others already wrote, with hockey it is much harder to have a historical mode comparable with OOTP. We can't generate ratings from stats, the NHL player database we use is less detailed then the Lahman DB for baseball, we do not have Play by Play data for old seasons.
So what can you (realistically) expect from us in version 1: a database with all NHL teams and players (with bio data and basic career stats). We found a way to rate player without rating them for every year they played in the NHL: basically, each player will get ability ratings for 5 points in his career (start, pre-prime, prime, post-prime, end) and a pre-defined template that describes him best so we can generate plausible skills for every year he played. It will be possible for the researcher to rate prominent player in more detail if the templates are not enough.
So what you most likely can expect from version 1 is the ability to start the NHL in the past, continue through the years, rookies will show up in the draft pool (or assigned to the real teams, your choice), finances will be modified to reflect the time and stats will reflect the years as well (at least stuff we have data for: scoring level, penalties).
I don't want to promise more, time will tell how much resources we can use for historical mode. But hey, even with "just" basic possibilities it is more then most other hockey games offer.
