You couldn't have said it any better!
It's clear Shipstation is not listening to users. It's been a week of hell trying to use V3 and not a single peep from Shipstation to improve the situation.
"Ridiculously slow" is the operative phrase. I timed how long it takes from when you click the print label button until the print preview pop-up screen appears for the label... 38 seconds! Thank God they didn't roll this out during the holiday rush or I'd be pulling my hair out.