I am all for removing add ons but there are and have been issues with the main UI I would like to see updated.
On my fire mage I use WA to show me when I have an instant cast proc for Frostfire Bolt and instant Scorch. The main UI only tells me when I have an instant Pyro Blast. All instant procs should be customizable in the new UI so we can see them easily instead of trying to find them within 20 other buffs.
On my holy priest I use a WA for Ray of Hope. My WA tells me if it positive or negative and the how much numerically. The base UI doesn’t tell you the amount of healing in a Ray of Hope. The buff just changes colors based on if it’s positive or negative. This makes it a complete guessing game where it can show positive but you don’t know if it’s positive 500k or 25m.
Overall I think getting rid of all the add ons is great but there are things that need to be fixed in the base UI.