Well technically there are 5 origin companions its easy for them to realistically fit in 7 after the origins more from the core books for the 12 base classes and probably an artificer in a dlc. As original plans based on what they said were the core 12 classes. Not all of those classes need the worm to do there own thing as I would personally hope that gets removed in chapter 2 leading to a more sinister plot as the worm will get old after a while.
Gale has something going on with the netherese. Lazeal has her own thing with gith progression. Asterion you have the Vampire bit, Shadowheart is missing part of her memories so i feel something like a chosen of shar plot or a twist between selunite background being hidden from her could go either way. Then will has the thing with his patron.
Kagha and Helsin // the grove makes for an interesting story line where you could basically choose the shadow druids / or the good side. Having to choose while i think its a nice idea to have all the companions having to choose brings some depth to it as your choosing between 1 class or another you experience something similar in Pathfinder WoTR and its one of the more compelling aspects of the story not being able to have all of them in 1 playthrough as that makes you want to experience more than 1 playthrough as oppose to just 1 shoting the entire thing it also brings in some diversity and change to the story based on how you go through it.
IMO ideally 24 companions with a choices that give you a total of 12 + the mercenary companions you make that's still a potential of a lot of diversity in the characters and a lot of plot to play with also more options could be added with more dlcs its something that gives depth to dlc content by adding companion options down the road. The subclasses are not such a big deal and you can tailor the characters to a subclass. Even getting them later in the story you could chose there progression as an option when you do get them. You still also have the main character so that is 18 which is a lot of choices and combinations you can do to make a party of 6 even. I do expect them to cap the core game somewhere between level 12 and 16 so. Based on the fact the original release was not expected to go all the way to 20. Which is good in a way as it makes multiclassing a much stronger option for mix matching classes as well.
Well it would be nice to keep all 12 characters i think being made to choose also brings about that division that makes you want to replay the game more. Having 12 vs 12 also leads to a much more interesting plot line because you still get 1 of each class just moved around so that your choosing the good companion vs the more evil companion. I feel that there is more depth planned to show more truth to the characters as well. Like despite that characters feel 1 way they may actually be a different direction under the surface I get that opinion a lot from the surface of Shadowheart. Like surface she's very much like a stuck up princess but as story goes on and you develop reputation with her she feels more like she is afraid to open up as a character. So that as the plot develope's you find out why her memory was wiped there will be more depth coming and she will actually end up being more likeable but its hard to see I cant really read Larions plans but that seems the direction they are headed with her.
It would be easier to work her in if they were making her a Selunite cleric in same way. But they could also kinda twist things and make some of the choices a complete suprise like maybe minthra is actually the good character and you cant figure that out till the absolute is defeated and shadow heart is actually evil to the core its hard to say there are so many different paths they could still take with it. Origins characters are more ment as starting alternatives to building your own character. DLC content I personally feel would be a better way to introduce more so it doesnt delay game release as much since you dont really need 12 character with there own unique story's from the start to make the game feel unique. Adding 1 to a DLC is a great way to keep the game pushing forward and expand on that in the future adding more to the base game bringing back replayability in all aspects over time but Id still like to see the core 12 character options available.
To me the ideal way would be 5 initials 7 additional characters later and then expand dlc content like:
DLC 1 - Artificer, Artificer character in the story added as an origins character... this expands even the beginning of the game. His own story expands into the additional content and you could extend the level cap to level 18 from 16. Adding a couple of extra story zones.
DLC 2 - Additional origins character expanding again the entire game encouraging a fresh play through. Level cap extends to 20. You get 1 new sub class for 6 of the base classes.
DLC 3 - Additional origins character - Alternate quests different items level cap not adjusted but speeds up and you get an additional subclass for the remaining 6 base classes.
DLC 4 - Epics levels extending with boons // level 25 using optional rules. 2 New races // 2 new artificer subclasses 1 new subclass for 3 of the base classes and a new origins character.
DLC 5 - Another new origins character, 3 more new subclasses additional questing zones and items. New Races x2.
DLC 6 - More races more subclasses more quests more items.
DLC 7 - Again More of the prior stuff continuing to add companions subclasses quests and items and zones.
You could build out from that and add years of replay ability to the game. The further you expand add the more you can do with the core game. You could even overlap and add more to it expanding with like Neverwinter//Icewind Dale ect as like full expansion games that could overlap with a complete new story that ties in as you progress further into there story archs but eventually tie in together giving you a new beginning to the game basically creating an expanding world that really could be taken to some serious depth over time. There is alot of room given proper attention to take the game in a lot of direction if larion really wanted to work with it. It could develops so far as an IP to eventually be its own expansive universe. But that all depends on how much they take it serious.
Right now they are not doing a good job in the faith aspect of that done properly you could release 15.00 dlcs with good content every several months and I know I would pay for them if they were done properly. and 30.00 - 50.00 alternate tie in expansions and if it added content to my game id complain in no regards. Totalwar: Warhammer 2 is a perfect example they created additional games tied into each other and even when a new game is coming out for it ill still buy the dlc content cause it can be carried over into the new game = mucho mucho $$$ for them and great enjoyable replayability for us as players. To the point you dont feel like you ever lose anything you just get an ever expanding ever more fun universe where the content is always good. To the point even 20 years down the road people would still buy the old content to get it in the new game. Someone new starts playing they want the stuff from the old game they would but it to expand there new game even more and the new game would still be interesting to existing players cause they are expanding there old game even more. Give you hundreds of thousands of hours of game play its what I think the true best way companies should be progressing with how to keep making money in the modern market. Its a much better system than concepts like loot boxes and subscriptions to games. Instead you just keep making your old content great combined into the new content.