Im used to getting full rosters of characters from day one in the good old Days. Why is this different now, is every character balanced to 100% and thats why they roll them out so slowly? (beside that I fully suopport this business model rather then new releases every 1-2 year)
Nah, you never got a "full roster of characters from day one". You had to buy the additions with another $60 purchase.
Think of it more like this: you won't get Super Street Fighter V 18 months after vanilla's release, but you get what would be in Super Street Fighter V over these 18 months. They are just now currently working on these characters.
Oh and DS4 is totally fine, use whatever you are more comfortable with.
The deluxe edition will definitely be enough for a whole new season of characters (or 600,000 FM), but probably not two of them, since that would be 1.2 million FM. Maybe if you really did almost everything and get all the weekly challenges, not sure.