They are vastly different armies. BT play differently, look different, and have vastly different fluff compared to EVERY other marine force.
No they are not, only difference is a few rules, that's the only difference between SW, BA, BT, DA. They have a few different rules from Vanilla that makes the more specialized in some way. BA are fast, BT have terminators, SW have their wolves and shit, DA have their bikes or something.
Fluff doesn't mean shit when it comes to rules, what is the difference between my Sisters killing for faith while BA kills for blood or IG for their commander. When you put down your models it wont make them any different. I might as well say I'm killing you to appease Nurgle but that doesn't give me any special powers.
If they could make the SM as different to each other as Eldar and Dark Eldar I'd be impressed but as it is every SM codex is just that, another SM codex. Heck even the new GKs turned into another SM codex, this time it's the psychic Spheezze Mehreeenez.
All SM chapters should be in the Vanilla SM book, all you have to do is copy paste the army rules and special rules on 2 pages from each SM codex and you are pretty much good to go if you add 1 page with the "unique" units each SM dex has.
And dont start with how much bigger it would be, it would max be 20 pages more and they could easily remove some fluff or painting guides.
Well, more time for me to expand my army I guess.
If it is indeed a WD dex as a stopgap, they might as well update some of the points costs in there to 5th ed.
Pfft, the only thing they will do is update the current PDF with the removal of the Inquisitors, Assassins and IST plus Karmazov. If GW has thought me one thing it's that they never make a PDF update that's worth it's download space.
They didn't do any updates at all with the PDFs before so why should they start now? The above is most likely the only thing they will do.
If they do indeed update the codex it will be VERY small changes, the above changes plus Rhinos now cost 35pts and they will call it a redone codex.
There is no reason they would update anything else unless there will be a model release with the PDF. Did they release any new models with the BA PDF? If they added something it would be the Repressor, it's the easiest kit to redo in plastic and is just 1 sprue to add to the Rhino box. They might even just sell the upgrade sprue but that wouldn't make any sense since then they couldn't charge you full kit price... or they might just do that...