The argument for this is simple: what makes classic WoW great to one player might be different from what makes it great for another. And who are Blizzard's designers to say which old features were just good or bad design for each player? It's an approach that shows Blizzard believes (at least to some degree) that WoW doesn't just belong to its creators but to its fans. That struggle between authorial intent or game design orthodoxy and "the player is always right" is at the heart of many of gaming's big contemporary controversies. But so far, Blizzard seems committed to its plan with regard to WoW Classic.
So committed, in fact, that modern WoW players are trying the beta and reporting what seem like bugs today but what were actually intended functionality 13 years ago. This became such a common occurrence that Blizzard publicly posted a list of known non-issues called the "WoW Classic 'Not a Bug' List." For example, hitboxes for the Tauren player race are much larger than those of other races. In a modern game, this would be seen as a serious balance issue (see: Apex Legends). But it's what vanilla WoW was like, so it has been faithfully reproduced.
This is the lamest excuse to try and pin it on a cash grab. Tbh this is just you complaining to complain, there is no issue. If you wanted to play classic on launch you'd have to sub before hand anyways you're still paying month to month you don't pay by week. The only way you'd lose that money is if you quit before your sub ran out later on down the road.