This content that forces you to buy cosmetics along the actual gameplay content is not the move, i'm not keen on paying 2.5 seasons worth of money for less than 1 season's worth of content.
A €10 pack would perfectly seal the deal for me, and i bet it would for many more players.
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I'm sure Bungie will take a look at the sales numbers and decide if they want to continue doing what they are doing. If it doesn't sell well, they will abandon it. If it meets expectations, I'd expect more or something similar. Wait 2 years and maybe the dungeon will be free.