Let's face it, you wouldn't be playing if you were truly 100% frustrated with the game. When SL is compared to BFA which was full of systems atop systems on system for a system to unlock a system for a system or to WoD where we barely got any content at all, you should be far more thankful for what you have now than compared to then. SL is the new modern MoP. People hated MoP when it was current then loved it when WoD showed its true colors.
Fun fact: The wait between 9.0 and 9.1 is the same amount of time that it took for WoD to release all of it's content.
But compared to 6.1 and 9.1 there's actual content worth doing. And 8.1 and 9.1? There's less systems. FAR less grind too.
There is no forced grind in SL like we had with Azerite essences, legendary cloak/vision farm, and stuff to slow down your progression. Anima is entirely optional and has only cosmetic rewards behind it. Your legendary is the only thing you have to work for but even then with 9.1 it'll be even easier to get. Renown comes from all forms of content and is also completely optional on alts. You're not forced to do the campaign on them. Remember trying to farm coins for your BiS corruption? Remember receiving only 1 option in chest? You don't have to do that anymore in SL. Remember appexis crystals? Exalted and revered reps for flying in past expansions? Yeah, you don't need that either.
People cried about waiting now those same people are crying about receiving content. Put on the big boy and big girl pants, take off the rose tinted glasses, and instead of whining, submit actual feedback about the systems you don't like. New content is coming. There will be content in 9.1.5 and there will at least be a 9.2.
WoW could be far worse.