One major thing they need is real time tooltip updates to give you the current cooldown and damages based on what your current stats are, D3 had this a huge issue as you can have like 60% CD reduction or huge bonuses to said abilities but it does not reflect it on each of the abilities when you look at them. If WoW a damn near 20 year old game can do it I am sure Diablo 4 can too lol.