Well, my final verdict anyway. I ask my fellow SAM players to share their opinions here if they are willing to do so. As for how I feel, the tl;dr is this.
It's better than it was post-6.1, but still not as good as it could be. I'm still having fun though.
In all fairness, I've rather enjoyed level 100 SAM. The nature of Tendo Setsugekka, Higanbana, Ogi/Kaeshi and all the supporting GCD's you need to do necessitates that it's impossible to fit All That Burst into a 9 GCD burst window (which, of course, is the standard number of GCD's you can expect to have in your average 20s burst window). This gives a bit of freedom throughout the rotation to utilize the second Meikyo charge for something else, instead of simply sitting on cooldowns and dumping everything every two minutes like literally every other job.
To that end, I don't hate the Tsubame change. On the contrary, I more or less enjoy it, but I really do miss having a nice easy-to-track timer for when my 60s burst should be used. Senei kinda fills that role now, but it did take some rejiggering of my hotkey setup to put it front and center like Tsubame used to be. Tying it to Meikyo does mean it's possible to get in with 3 Sen and throw out a Tendo/Kaeshi combo with essentially the press of a button, then get an easy follow-up Higanbana and continue from there. Overall, there feels like there's some more potential flexibility to the job, although this is obviously a pre-savage opinion. I'm sure someone with more time and patience than I will eventually be able to make a GCD-by-GCD map out of the SAM rotation on a per-fight basis, tailored to each possible GCD tier. If they haven't done it already. And that's fine; it's good that this sort of potential optimization exists, even if I'm simply too old as a gamer to successfully do it, or even care to try anymore.
Timing considerations aside (some of which comes down to BRD and DNC both having 110s CD's on their buffs, which some people still don't seem to be aware of), I enjoy that there's a bit of free form capability with when and how you use that second Meikyo charge outside of the opener.
Zanshin....exists. It's the new Senei, and Senei/Guren are just super versions of Shinten/Kyuten. That's fine too. It at least forces a little bit (just a bit) of Kenki management every ~105s or so. It's nothing special but it's functional and gives a reason to pay attention to your Kenki gauge, even if it's just for ~12% of your two minute rotation.
Lastly, I'd like to sing the praises of Tengetsu. It was a small change, with the delayed self-heal, but comboing that together with the Kenki gain actually does add a good bit of engagement to things. Enough raid wides or other party damage goes out that you can keep getting good value out of it, both in self-sustain and for extra gauge, such that it adds something of an extra meta-game on top of the usual combo-and-mechanics bit. It's a small but significant change, and, imo, is at the level of standard I would like to see all changes follow.
All of this is to say that I'm pleasantly surprised with SAM at level 100. What I still don't like is the process by which we got here.
I will say again what I know is on the minds of many players; what was going through the collective heads at SE to let this kind of thing happen? Had they held off on removing Kaiten until Dawntrail release, with the true reason behind the removal (50% potency was too hard to balance around when it came to adding new skills instead of that song-and-dance about "button bloat" or "action bloat") and the steps they were planning to take in order to maintain SAM's overall sense of feel, I think we could have avoided that entire incident back during 6.1. To this day I can only assume that Yoshi P., having been caught up in the imminent release of FF16, only gave the Kaiten removal a rather cursory once-over before approving it due to his attentions being focused elsewhere. He trusted his team and, in the end, his team made a bad call and let him down. A call that Yoshi P., to his credit, endorsed and supported despite the negative reaction, but one that ultimately soured a lot of the community on something that many perceived as not even being a problem.
To be fair, I understand the reasoning behind the removal of Kaiten, and I do think - largely on the back of Tengetsu - that some of the conscious "resource management" that was needed in this post-Katien world has been restored. Instead of simply maintaining your 20ish gauge for Kaiten, you're now rewarded for keeping one eye (you could even say it's your Third Eye maybe? Eh? No? Ok fine....) on Tengetsu with the goal of maximizing it's use in the best way possible. It's absolutely not the same as Kaiten, but it does bring it's own flavor to things that I've found myself enjoying.
I just can't stop thinking that things didn't have to be like this. All it would have taken was a section during the Live Letter explaining the need for Kaiten removal followed up by information on the direction that they were going to go that would maintain the overall feel, coupled with actually doing it between xpacs instead of smack dab in the patch before the first new Ultimate in years was released. Can't undo the past unfortunately, and for what it's worth, it does feel like the job balance team cooked decently well with SAM.
How do my brothers and sisters of the blade feel about Dawntrail SAM?