The entire reason the glyph system exists now is cosmetic customization, and yet it generally offers very, very little of it. The system has a ton of room for expansion, and I think it’s about time that happened, don’t you?
Glyphs were once the primary function of inscription, don’t leave them in the gutter like this, Blizz.
I think Blizzard is trying to slow down the roll out of new glyphs so they don’t “run out” of new glyphs. Hence getting a few new glyphs with the expansion, plus a few more with 8.1, and likely a few more with 8.2.
I have also wondered if their is some confusion on how to handle inscription with the new tier system in BfA. With Engineering, Blizzard could always add new patterns each expansion to replace the previous expansions patterns, just like with gems and enchants. But glyphs are spread throughout various expansions and the majority require leveling in the Broken Isles.