Thirdly you say why should someone who wants to play the fantasy of BLM be forced to not play it? I'd argue they should have delved into it before if they liked the fantasy and at least played the basic rotation which in itself is simple. No one forced people away from BLM aside from themselves. The fact that they didn't leads to believe they weren't interested enough in the first place. People with a passion would have overcome this trial. You've only invited people who have had this class in mind on the back burner or had no interest in it in the first place and there's no guarantee it will stick with them. I find it extremely odd you say of all the things that are making you sub to the game it's the simplification of one job. And this entire line of argument is don't gatekeep the fantasy people want to play when no one is doing so, but let's sacrifice what people already like about the class so they feel forced to play something else instead, isn't that a bit contradictory?
And lastly there are plenty of examples of requests from players requesting more engaging jobs alongside encounter designs. It shouldn't be a sacrifice of either one to get the other. SMNs have been asking for it, all of the healers have been screaming for it, it's been multiple expansions for some jobs, its only been loud from BLM most recently. If our current job is starting to feel stale switching to a different one should give a fresh and exciting feel, but if they all play similarly because of homogenization due to simplification then you are going feel the stale about the new job quickly.
The topic of third party is entirely irrelevant, you just made a whole broad statement implying everyone is using third party to simplify encounters while asking for complexity, in itself is not true. And third party should not be taken into consideration when discussing design choices.