While it probably isn't fair to judge a game's story or other elements that simply can't be explored within an hour, I think it is actually perfectly feasible to judge whether or not a game is worth putting any more time into. Within an hour, a player should have been given an interesting enough introduction to the world, mechanics and if applicable, story. In the time, a player would or at least should have a chance to see many of the game's mechanics, or at the very least experience the main "gameplay loop".
By "gameplay loop", what I mean is the main part of the game which, if we were to take a vertical slice, what would the player be doing in that time. In most modern console shooters, it would involve some combination of running for cover, aiming down sights, reloading, ducking, using an ability on cooldown/throwing a grenade, etc, etc. In ME: Andromeda, right at the start on the prologue mission, the player reunites with Cora and they defend themselves against alien aggressors. That fight sequence is the "gameplay loop" for that game. All combat is more or less like that (obviously excepting available weapons, abilities and stats). That fight is absolutely representative of the game's combat and it is absolutely fair in this example for a player to play thru Habitat 7 and know whether or not they'll like it.
I'm sure I've come across posts and reviews in the past where players or reviewers have said that it takes a few hours to get going, or the first few hours weren't great but it got a lot better after that, things to this effect. If that is the case, the developers have made a bad game, or at best, a good game badly. If the first few hours of your game are bad, remove them.
