I have many theories about Street Fighter 5- I don't actually expect it will be a traditional free 2 play title, something similar to killer instinct or Dead or Alive Ultimate maybe but unlike KI , there will be a standard disc release version of the game.
My prediction - There will be a handful of small arcade tests done in japan with the alpha version of the PC edition. It will have only 8 characters or so, just to fine tune whatever new gameplay ideas they have (the VERY brief look within this trailer seems to indicate that perhaps the player can charge up some kind of attack independent of SF4's super or ultra gauge - like gathering chi in dragon ball - as well as possibly having air combos/juggling becoming more prominent). After this , I suspect an early access/paid beta program will be enacted , anyone that pre-orders the game through PSN will have access to a full beta edition with 8-12 characters. This beta edition will be made available about 6 months before the game comes out and it will be playable for 30 days followed by a 3 month shut down and then a 14 day online test followed by a break until the game releases.
I think it's a safe bet to say it will launch with 18 characters but unlike street fighter 4, this version will be marketed as a platform. What I mean is, once you buy the disc or purchase the digital copy, every future enhancement will be DLC. The Disc release will also be updated every 12 months as well so that new owners are always jumping in to the same experience as everyone else but you would never HAVE to buy the disc.
To that end I expect the game will largely be shaped by the community after that initial release. I'm going to guess out of those 18 characters included day 1 , we'll see 14 characters returning from Ultra Street Fighter 4, 2 more classic characters from any of the accepted main SF titles or even final fight and 2 brand new fighters.
Taking it one step further , I think those 14 returning characters will be based on the 14 most popular characters in USF4, popularity as based on overall usage worldwide based on all current editions of the game. Tier ranking wouldn't factor in.
Obviously , as mentioned above I see them doing at least an annual update, I think this will be handled in the form of a season pass. Spend 60 bucks on the initial game - you get 18 characters and 12 stages with all the essential modes as well as beta access if you pre-order before the end of next September. Season pass would be 24.99 if you purchase it within 30 days of the games release, 29.99 if it's later. I would expect 3 content packs to follow in each season. These packs would be 12.99 separately to make the savings better for a season pass holder. Finally, each content pack would include 2 more characters , an extra background and 1 set of extra costumes for each character. So , a year after release the game would end up with 3 extra stages and 6 more characters as well as 3 costume packs. Out of those 6 characters, owners of the game would be able to vote from a short list which characters they'd like to see next. So perhaps capcom would be working on 8 characters at the same time and the audience basically choses which ones they want earliest / latest.
The 2016 disc copy would then have all of this DLC on disc but it would still cost 50$ to buy the game at retail. Legacy owners would then get a discount to buy a season 2 pass for just 19.99 for an early buy in, 24.99 for a later buy in and new owners would have the 24.99/29.99 pricing.
I could see capcom milking this setup out for 4 seasons of content. So by the time it's all said and done , you'd get 42 characters , 24 backgrounds and 12 sets of outfits for every character. Players buying in from day 1 that decide to buy everything would end up spending 145$ over 4 years.
As well, the game would have a demo edition for free, maybe it has a rotating sample of characters , instead of selling them ala carte, there would simply be an upgrade option, make the trial the full game for XX$ and then you can buy the DLC however you want.
