Yes, nearly: DSA currently only supports a few basic offloads, and all?/most of those only work on some of the supported DSA targets. I think, MT76xx devices are the most "advanced" in that respect right now. But nothing "advanced" like even pppoe-offloading (yet).
I just hope, "flexible" doesn't come with a large "Difficult-to-audit-caveat" side-dish. NPEs "governing" traffic could potentially substantially reduce the trust the user can have towards the platform.
No, I don't know of any problem in your reasoning. I'll look forward to that happening! I wasn't aware newer hardware was so flexible.