My .02.
I read (and watched) the OP, and some of the commentary that followed.
The bottom line for me as a fan is this:
I highly respect JLB. And I feel he always gives a great performance on the studio albums. But live, he has ALWAYS been spotty. ALWAYS. I have seen Dream Theater more than most, but less than a lot of the hardcore fans here (16 times from 1998-present). It's always the discussion between my wife and friends - will we get the consistent JLB tonight, or the spotty one?
On the Distance Over Time tour, we got the really good James in San Francisco. I enjoyed it a lot. That followed the very spotty and cringey 2017 IAWAB show in Oakland. Then I went to Oakland for the AVFTTOTW tour. And he wasn't that good. The effort is there while performing. He's not mailing it in. But clearly, whatever approach he's taken to his live singing needs work. And I really think those who deny that are being silly. JLB struggles live, very much so now. And hopefully, he's working with someone now to help him sing more consistently.
Certainly, "the voice" is still there. He can hit and hold notes at home, in the studio, etc. But singing live, the travel, it's all very different for different people. For my money, before the MP reunion, I decided that I was done seeing Dream Theater because I was unsatisfied with the live vocals for the amount of money we now pay. I've seen DT 16 times, do I really need to see more? I wanted to retain some of the memories from the shows JLB was singing well. But now, with MP back, I'm fully on board to go again. But as a fan, I really want to see JLB, the sunset years of DT, be more consistent live. And I think he can.
I think part of it is working with different people, and finding a strategy that he's comfortable with and works. I think another part of it is flattening some things (as Ray Alder did with Fates Warning), and not going up so high to sing things. I also think the band needs to do him a favor. I don't know what tuning they are in, but guess it is standard. I hate when bands drop a full step, as it sounds like mud. But a half-step has to make some sort of difference. Experiment with dropping the 90s stuff a half step. See what still sounds good, and what doesn't. Whatever sounds good, play that. Whatever doesn't, don't play it anymore. Even if it is "Pull Me Under." Or, simply re-arrange stuff and do it differently. Whatever makes the entirety of the performance the most consistent.
The human voice is so very unlike any other physical instrument. I fully support JLB, and root for him. But I also would like to see both he and the band really work hard with and for each other, to make the vocals more consistent, and...also make sure they are very live. If that means MP and JP singing a lot more harmony, work on it.
At the end of the day, as long as the effort is there to make the live show, particularly the vocals, consistent, and we see that effort, I'll support JLB. He deserves that. He IS the voice of DT.