Honestly as someone who plays DNC at a high level, the tillana thing isn't a huge inconvenience and it's fine to play around (aka trying to use it when I'm super low on gauge and just eating the gauge loss if it means fitting tilana inside of burst) but it's just annoying.
I really don't think that changing it into a buff instead of 50 gauge is going to make the job "more braindead" than it already is because people on the low end will smash it blindly like they always have, and people on the high end will smash it within burst window like they always have and get the tiniest bit of damage out of the gauge they didn't lose. In my opinion, the only situation where the gauge lost really matters is in specific comps in high-end content where you just roll like a god on RNG and get a million procs a second and your damage numbers actually matter, but no one in that kind of situation is playing the job at a rudimentary enough level for you to consider them a casual by any means and they probably have a million other things on their minds and ways to express skill like doing mechanics and doing weird ss alignment/uptime things depending on the fight.
With all that being said, I think the only possible excuse for DNC not having tillana give a buff like RDM manafication instead of 50 gauge is maaaybe the buff cap, and even then I'm more inclined to believe it was an oversight when tillana was changed probably later in DT's development. Why they haven't fixed it all these patches is beyond me - Maybe they're gonna change it again in 8.0. If they aren't, I think they should just give it the buff treatment like manafication so people who care can be less annoyed during burst, and people who don't care/notice can keep playing the way they were going to play anyways. It's just a QoL thing.
Also I can't be bothered digging through the ongoing argument in this thread but overcapping on gauge with or without tillana even when you do everything perfectly is entirely possible and very dependant on RNG and other factors like whether you have a MNK or whatever. Sometimes you just go into burst with 45 gauge and you literally can't burn it before techstep is back up. Sometimes you just roll and get every single proc between GCDs, or during one of the two GCDs you have to reserve early in burst for last dance and finishing move if you don't want to/can't/shouldn't drift them. Sometimes you don't have time to burn gauge because of a phase/arena transition where the boss becomes untargetable but you have to start techstep early to align with the party.
No matter what you do on DNC, you'll probably overcap. Things happen and it's disingenuous to lump it all into a skill issue. The least they could do is make our lives a little easier by tweaking tillana so it doesn't contribute to the problem.
