This take is so ridiculous I have to assume it's a troll, but I'll indulge you for a moment.
Do you, as a Red Mage Main, post on the forums about all the aspects of the job that work right on a consistent basis?
No one brought up Kaiten in 4 years because SAM was seen AS PERFECTLY FINE as evident by the iterations we got for each expac and from the lack of outcry of SAM players at large. That's not to say there wasn't room for improvement but at its core players were happy.
The developers fucked up, full stop. SAMs gameplay was largely lauded as being as close to perfect as you can get (in terms of job flow and feel).
IF SE really knew about this issue they should have changed Samurai in a meaningful way AT THE LAUNCH OF ENDWALKER.
Additionally why did they give us a lvl 90 ability which is literally the most extreme version of the abilities they now say they have a problem with? (long cool down, super hard hitting abilities that vary wildly based on crit).
SE either had no idea this was a problem until just now or it was along standing issue they chose not to bring up ever . . . both of which aren't good looks for them.
And really, what's at issue here? SAMs never ever had issues clearing content or pulling in good DPS. Is it that Ultimates were causing issues? Well good news, NO GROUP IS RUNNING SAM TO CLEAR ULTIMATES.
Having a job that's built around big hits isn't an issue. If variance is an issue then give kaiten a buff to crit change. If crits are an issue . . . well maybe there's a fundamental issue in how encounters are designed.
Lastly, you bring up the burst as if its a bad thing or was something the devs were targeting. Samurai isn't the issue they are trying to stop. They wanted more consistent damage to make their balancing easier which is just another way of saying they want to be lazy about it.
If they DON'T want to have bursting, hard hitting jobs then they need to replace SAMs kit with something fun and meaningful. The whole kit was designed around the concept of build up + big hits to give a very rewarding gameplay loop. If you just rip out parts of it you get what we have now: pissed off players.
It isn't our job to provide feedback on how to fix changes they just dropped on us, it's THEIR job to figure out how to make jobs fun and engaging.
It's simple: bring Samurai back to how it was in 6.08, then for 7.0 do a full revamp to fit the needs of SE.