it‘s a single-player offline game, we‘re playing with ourselves on the pc, you‘re not sitting with other folks around the table. You‘re supposed to be allowed to set your own rules/limitations within the given rules. You want to tackle Firkraag with a party of 4,5,6 or even solo, that‘s up to you. You want to use spells before fights or not at all, up to you. You enter the druid grove and decide to not rest at all, rest once, rest twice… up to you and so on and on.. You want to try to even break the rule, go ahead be creative, go with a high charisma reload when necessary and try to finish the game with Xzar/montaron and Jaheira/khalid. Hell, there‘s people who separated pairs in BG1. You want to use moving to fool the enemy or even use kiting, up to you. Trust that people are capable and willing to learn, allow them to set their rules within the system, allow them fun, we‘re all different.
I am all for giving player a choice - if you don’t want to deal with combat you turn difficulty down. If you want to try going solo, you go solo. However, these are all self imposed limitations to make the game harder/easier consciously breaking the rules.
Job of game designer is to give you a game with an entertaining set of rules. What is entertaining is subjective so it is beneficial if the game is flexible enough to accommodate a wide variety of players. But it is not up to player to make up rules or not use existing features to make the game fun. Most gamers have a natural drive to play optimally. If one option is strictly better than the other why would you use the weaker one? It’s like putting an overpowered unit in chess but expecting you to figure out to not use it.
Giving you ability to run with all companions at once is bad. Sure, they could balance it around 5 characters and than expect people to figure out that most fun they have is by playing with 5, while giving a wider option to people who just want to run around with everyone. But how do you communicate this? How do you stop people who want to have balance combat by not taking with them too many units? Why do you even waste time creating UI for an amount of companions which actively hurt the experience. It’s like giving a sos to a meal which doesn’t fit just in case someone one day might want it. You Are a Chef, and it is your job to compose a good meal. Whenever someone likes it or not it’s up to them and they can decide whenever they want to eat your stuff or not. Or they give feedback and you adjust or stick to your guts. Coupled companions in BG1 are a good example. They were limiting and people were abusing game systems to bypass them. That’s why they are not present in BG2. Obsidian did 6 man party and decided it was too much. If the change to 5 won’t be a good decision thy will probably adjust for the next installement.