Problem is , there is a slippery slope. People buy these Season Passes blindingly and Devs will start develop their games for DLCs from the start , kinda like "Day 1 DLC" .
Example where things go wrong: Total War: Warhammer . Guess what, the 5th faction (Chaos) is a DLC, the game is not even out yet and they are doing this. Stripping the game of content and putting it in the DLC (be it pre-order or season pass) . It's like Blizzard giving you StarCraft 3 and saying Protos is now part of the Season Pass.....
So in a way, Bethesda not even knowing what to put in the DLC is a good thing, because it means they didnt intentionally strip out parts of the game to fill up the season pass ....but if everyone just buys the season pass "anyway" , how can this be good for anyone?
It means game prices will become $100 for the same content very soon.