First of all, I am gonna say - good job and many thanks for the guide!
Though I'd love to note that this guide is,
in my personal opinion heavily oriented on single target raiding scenarios. Don't get me wrong, I would mostly agree with it because that's where arcane stands quite strong.
However, from the the few arcane mages I get to meet in raids and M+, few have trouble with ST.
It's the other situations where they fail. AoE, such as Mistress, or semi-aoe, such as Harjatan, or, perhaps most of all, M+ where you need to adapt every week, Different trinkets/talents will work there.
Hence I'd like to point out that, for instance, Charged Up is NOT a waste, even without Kilt and especially if you aren't a robot and don't know every possible encounter from the top of your head. If you find yourself without charges in crucial "omg kill the add" situation, you are useless. CU can help a lot while allowing you to converse mana longer and then transferring to burn phase at an instant.
Another story is Arcane Orb talent. That one is IMO underestimated a lot. I am using it every second week in M+ with fortified, and I am talking +15 mythics now, where some mobs just don't want to melt that fast. I mean look at total duration of M+ run - most time is spent killing adds, not bosses, so being effective there gets you a lot of extra time. Even if you have Mantle for AoE, you can/should still take Arcane Orb talent for insane numbers on every group. On bosses it help building up the charges on demand if nothing else. But note that even in M+ there are bosses with adds, such as Harbaron (Maw, 2nd boss) where killing fragment asap with aoe helps.
As for (semi) AoE raid bosses, the talents there depend IMO on your agreement with your team. For instance on Mistress HC I am often going full AoE (Resonance, Arcane Orb. Mantle) and take out the adds while other people are mostly ST with some random cleave on top and we are fine that way. By this I want to point out that the AoE capability of Arcane is really good as it keeps scaling with number of targets. Not to mention mana isn't really a problem there.
The only really weak point is constant cleave, 2 target bosses and such. In those cases, we just go back to ST no matter what.
Perhaps the last point I would like to make is about trinkets - don't go all crazy about owl. It is indeed and by far BiS trinket, but that holds true only for ST and it gives Mastery as stat. Remember to swap this trinket for other situations
Again, thanks for the guide, don't take the babbling above as a challenge to your guide, it's merely a pinch of personal experience with arcane mage.