Well certain complaints that some people have, including me is that episodes 18, 20, and 26 are almost filler throughout the episode, and suddenly due to a few seconds of an important event happening, it becomes essential, even though those episodes are actually quite boring imo. Furthermore, SM has a lot more to show than XY or any other series had to show since there are 11 equivalent gym battles, the whole AF and TS plot with the Ultra Beast, an arc for Lillie with a possibly of Nebby, etc. So there's also a risk of everything getting rushed.
And about the whole trial and grand trial being rushed, I agree. I feel that he should've gotten the Normalium Z as per normal, lost to Hala due to not being experienced to pull of a Z move, practice, and then beat Hala in the rematch. That would've made the pacing feel better.
Anyway, I'm quite confident that the series will come good again after the whole Akala trials start, and the plot gets thicker.