My Preferred Changes:
If I really wanted to take Arcane Power, I would just take the sigil that does the same thing on a 10s CD and still isn’t worth taking. The CD should be 10-15s, tops.
Glyph change was a good start, but glyphs are still terrible for many reasons exhaustively expounded on previously in this forum. Honestly, they aren’t ever going to be viable outside of storms for PvE at this point.
I disagree on harmony personally, the buff was kind of needed the heal is really weak in the first place and the glyph adds a unique mechanic then just simple healing. Even when attuned to water the heal was lackluster in pvp/wvw situations.
Elemental Harmony definitely needed a buff. I’m not sure if the one it got will help it enough or not though (Inscription trait really needs to be moved to another line, maybe water). I guess we’ll have to see? I do like your idea of it sharing boons instead. Sharing Arcane power would be interesting as well, especially combined with Elemental Surge.
I was sad to see Wash away the Pain and Attunement skill cooldowns get nerfed, but I understand why they did in many cases. I wasn’t pleased with Lava font being doubly nerfed (combined with the Pyromancer nerf) but if that leads to some buffs for Staff in Earth/Air I’ll be content, less cast time for Air2 and less delay on Earth2 maybe?