Yes. a bad fluff spin to justify another money grab forcing (in long term) all SM players to rebuy their models in order to field Super-Space Marines aka StormCasts. Sorry about the negativity
Exactly. New tactical supermarines have already bigger bolters so sooner or later they will need to get bigger equipment for other units (devs, assault, terminators). And people will buy it and they will be set for decades.
Regarding the starter set, rumours on SM part are this - Captain, Librarian, Tactical, Assault and Devs. Seems pretty weak without vehicles (they have not been rescaled yet?). So I've been wondering, will all those marines will rescaled in starter set or only tactical squad ?