On Beta there is a long setup before you even open. Everything seems to be on the GCD and the dmg outside of burst is so poor you go from top of the metres to bottom outside of cooldowns. With the 3 minute cooldown on AP (obviously can be altered by conduits and covenants) this means no viability in M+ at all. It has been the worst mage spec since HFC in terms of numbers alone, and in HFC it was just broken because of the trinket. The redesign in Legion started off wonky with Quickening where you'd actually not press anything for ages.
The new talents don't add anything to the gameplay that we don't already have. It seems the class is designed and then there are GO TO "choices" to be somewhat viable in maybe 1 aspect of the game.
Single Target opener = 10 seconds of setup and then 1 button until oom
Single Target conserve = 3 buttons
Single Target mini burst = 3 globals and then 1 button
AoE = 1 button and sometimes 2 depending on number of targets.
Mobility in Shadowlands is odd too. Displacement has been removed in the name of homogeneity. I don't think anyone said displacement makes me feel like I'm not playing a mage, they feel different in a bad way so remove it. Altered time is great but why did they remove Displacement?
They should bring back Displacement and make Arcane Orb or Nether Tempest baseline. They should also remove the GCD on some abilities. If you go Necrolord you need to add another GCD to your opener. It really makes no sense.
No one is actually talking about this because other than in PvP no one really plays Arcane. Everyone mentions Spriests but they've been top tier in terms of gameplay and DMG throughout Legion and BfA.