I feel like there are multiple discussions going on and sometimes the points of argument are against not the exact counterpoint.
If we focus specifically on these new paid extra hours (both morning and evening), so far the dates that have been officially announced are when there were not EMH planned (so not taking away EMH) and before or after the park opening times (so not impacting regular park hours).
So I see two arguments against this developing:
1) I don't like how this "feels" as it is Disney nickel-and-diming people and a cash grab and creating different classes of guests - those that can pay the extra and those that can't. I think there have been enough things pointed out here that there has always been that split (with character meals, ticket books, vip tours, etc.) - but this might just be a bit more in your face. I also think that coupled with the cuts in other areas (eliminating CMs, taking away FP+ for parades, maintenance not what it was, etc.), even though these extra hours aren't directly tied to that, it feels like Disney is cutting back the "base" experience while adding these additional experiences that require a guest to pay extra.
2) Projecting these actions onto "what might come in the future" - that is, if these go well they will add them to additional nights and either get rid of/reduce EMH or have the non-EMH days close earlier than in the past (that is, in the summer MK was often open to midnight or 1am, now perhaps they close at 10pm and have these extra hours after) or, in the case of taking away the FP+ for parades, etc. - start charging a fee to be in those spots. I fully agree that if these "extras" start taking away more directly from the "base" experience that is not good and will upset me. But, if we are being fair, this is speculation on our part and not anything officially announced. And to get upset about things that might happen can be dangerous
I think the trouble is that so much is happening at one - cut backs due to overruns in Shanghai, feeling that care and maintenance is going down and CMs don't always have that "pixie dust"feel, crowds that make the trips more of a chore (be it dealing with them or having to plan things out with FP+) ... and then they are adding experiences one after another that cost extra - so looking at a macro sense, they are lessening the base experience while wanting you to make that up with extra experiences.
I think that if Disney did more of the "slow boil to the lobster" technique so we didn't notice as much it wouldn't be perceived so negatively. Also, if we stick to only what has been officially announced the changes really are more "extra" than replacing free with paid experiences - but obviously everyone's experiences are different and can feel how the feel about things - and I can understand all of the news lessening the "magic"