I mean, that's all fair and I'm not trying to dissuade you from what you like, it's all subjective. My only point is that it's objective that all the things you like about the Stones never would have existed if Brian hadn't been there in the first place. I agree with you on the last bit btw, it had run it's course and there was no coming back.
I will say you are definitely in the minority on Under My Thumb though, almost everyone involved has admitted the song wouldn't have even come out if it wasn't for Brian's addition. Also weaving with Keith came from him btw.
Somewhat of a tangent, but my honest belief is when people say they enjoy the 4 album run, they are really saying they like Jimmy Miller. Because Beggar's and Let it Bleed are much more like Aftermath and Sticky Fingers and Exile are more like what followed. I really had an epiphany when I read the All the Songs book I mentioned earlier when as I said it dawned on me that all of my very top Stones songs predated Mick Taylor, and what I realized is the Stones really lost their edge by the time Sticky Fingers came out. And I don't attribute this to not having Brian Jones fwiw. It's just understandable they had reached a level of comfort at that point, their relationship with straight society was totally inverted and you feel it in their music. The earlier stuff through Let it Bleed was just so much harder. Paint It Black, Mother's Little Helper, Jumping Jack Flash, Sympathy, are all just straight up evil ass songs. And a big reason Some Girls was a return to form is they actually recaptured some of that edge with all the tumult going on.