We say rage starvation because you have considerably less rage than live in effective terms, and that means you get less tactition procs which in turn means you're affected more by RNG swings, have less effective use of rage. So when people say rage starvy they mean they cannot play as they do on live, that means the spec is slower and more subject to RNG playing a major role in the outcome of your dps.
Lack of tactition procs can cause heavy rage starvation that has nothing to do with player error. If you account for a DOS equipped player then your numbers between live/ptr should be similar on ST while running the same spec (aka FR/AM/DC/Dauntless), but the variance through RNG on PTR is much greater than it is on live, less consistent.
They have essentially accentuated the negative aspects of the spec, intensifying them while tuning up the spell numbers to compensate. The buffed other talents fix none of the issues with the spec. Non FR specs still can't effectively turn rage into damage and so have an excess of it, so FR is still a requirement and Avatar is still too valuable to drop it for Ferver.
Edit : And as for the APM, Arms has nothing on Gladiator. As someone who has dealt with RSI (still do) and needed physical therapy for it I can say I don't have an issue. If you split the workload between both hands it's pretty light work. Compared to say typing for a living or being a musician it's nothing.