Pushback occurs whenever players think that the job differs significantly from the way that it 'ought' to work. Jobs that play differently from their previous series incarnations will get pushback. How many times since Heavensward have we seen requests to change DRK to use HP as a resource, or use a scythe, or to be changed into a DPS job? Likewise, jobs that play significantly differently from their previous reworks will get pushback as well. Which is a catch-22 situation, as the entire point of a rework is to change how the job plays. Yet you will invariably have divisions within the playerbase each demanding that the job play closer to various designs (FFXI DRK, 3.x DRK, 4.x DRK, and 5.x DRK). Ideally you just try your best to capture the spirit of various iterations while accepting that nobody will be entirely satisfied.
The broader issue with SCH is that SCH has been a very powerful job for the majority of this game's history. Much like WAR, there were a lot of advantages that it was grandfathered into in 2.x that set it up to dominate for expansions to come. Naturally, the dev team have systematically been curtailing these jobs' power to bring them in line with the rest, but it has taken them the better part of several expansions to do so, with their respective playerbases fighting tooth and nail to cling to those advantages. The majority of job nerfs, as you may have noticed, deliberately happen silently between expansions when players haven't been able to test how the math will work out. Everything outside of that is 'upward balance' to keep everyone happy. I personally think it's much too polite of an approach, and sometimes you just have to be aggressive with balance changes to ensure that there's a level playing field for all jobs. I'm glad that we're starting to see more of that now.
Enhanced Unmend has always been an odd trait. Historically, it used to remove the MP cost on your next Unleash, and it was equally strange back then. But I think mobility actions on tanks have needed a second look for a long time now.