A more accurate statement might be that DMs have no control for Adventurers League, because as I understand it DMs have other restrictions on their preferences than simply being forced to accept what is legal, and that if they want to control everything they should DM for a non-AL game.
That's not really a fair answer though. I can like how AL is right now just fine, with the current number and type of options. I don't need to "control" it all, because the existing setup is already well within my realm of acceptability. But if you increase the number of options, you increase the risk stuff will enter that I don't like. So it's not a matter of wanting to control everything, it's just a matter of the number of options crossing that threshold from acceptable to unacceptable. The idea that material can only be objectionable if you feel the need to control everything is extremist, and not really a fair way to examine the issue.
If that's the case then the approval process should be done by the DMs as a group, and that's a kink that should be worked out as part of agreement to round-robin DM. The agreement can require a majority or unanimity, but some kind of agreement should be reached.
First, a DM who won't be DMing until well down the road might have no idea in that moment that an option will or will not fit with what they plan to do - they may not have their plan ready. Inevitably this will eventually be the case, as round-robin DMing is almost never between DMs who have planned years and years in advance.
Second, this answer fits in the "you're doing it wrong - you should adapt your methods to meet my goals" series of answers. Any time you find yourself saying "then change, so that I can have my options" you're no longer arguing that it's no skin off my back to simply say no. DMs have been doing round-robin style gaming since D&D was invented without the need to suddenly consult with each other on that level of detail about future plans, and asking those DMs to suddenly change so you can have your options seems pretty unreasonable to me.
Because the design experts are also not experts? If the experts are actual experts and if there is a proper process for review, then any problems that arise should be limited to being minor in nature. It only becomes an issue if there is no proper review, perhaps because the company is rushing the book to the shelves.
We had a LOT of PHB review, and still there are problematic things in that book. And you expect splat books - and an increased rate of splat books at that - to be more flawless than the PHB itself? It's inevitable that things will not work quite as planned, and the risk increases the faster the pace of publication and the more options provided. In addition, the emphasis was on "in their campaign". The experts have no idea what each individual campaign is like. An option might work for most campaigns but not a particular one, and as I said you may not know that right away given the nature of DMs not being game design experts and campaigns developing over time and options running into problems over time.
Bottom line, it's a legitimate issue for more options.
With regard to taking an option back, yes, it is naturally harder to do once someone has chosen it because you then rely on the maturity of that person and the persuasiveness of your reasoning for removing the option. However, the notion that something in the future that is published affects the previously-allowed option in a way detrimental to the campaign assumes that the DM doesn't also assess the future material before integrating it (or that the DM didn't do a thorough job of doing so).
This fits again into the "You're playing it wrong" category of answers. If you seriously expect all DMs to be so good at assessing future game content for how it will interact with all past and future content in a changing campaign such that they can know up front every time if something will work out well or not - then I'd say you're putting an entirely unreasonable burden on DMs.
As far as developments in a campaign causing a problem, that can happen even with the existing options and is not a reason to not have them available for those who want them.
The more options you have, the more risk of it happening. That's my point.
Sounds like an excuse for shoehorning too much new material into resources that fans of older material want to use. just because you create a duelist class or subclass doesn't mean you have to shove a duelist NPC into an adventure. You can suggest the possibility of changing that NPC into a duelist, but the NPC should work just fine and have the appropriate flavor even if you are not using the dueslist option or the book that it comes in. Paizo's failure to recognize that you don't have to shove new options down people's throats is not a valid excuse for not creating more options, it's a flaw in the execution of their products.
Or it's a highly likely reaction to fans who buy those materials who want to see it supported. You're simultaneously arguing WOTC should listen to that same sub-set of fans demanding a greater rate of publications and options, and then ignore those same fans when they demand those options be supported in the future. But really, what we have is basically one example out there (the example people constantly point to) of how these things tend to develop, and you're saying "well they are just doing it wrong". Maybe, or maybe that business plan sort of dictates doing it that way which is why Paizo went down that road and continues to double-down on it. I am betting their market research is pretty strong. It means they alienate those who don't like more and more options, but cater well to those who do and who want them supported.
WOTC is going down a different route, obviously.
