Don't think self-interested companions should be mandatory by any means, but perhaps they'll implement something like the AI options (self-interested to death, vocally self-interested but won't fight, cooperative, etc.) they have in D:OS where your party members will respond in dialog as they would to uphold their interests, though not sure if they ought to take on AI control for combat, nevermind leaving the party. I'm not sure basic AI for dialogwould take all that much more testing than is required anyway since the AI would just be making decisions that are already available to players anyway (they added AI for your fellow source hunter in D:OS1 in a single patch, if I recall). I think the AI for dialog (or combat) for party members would actually be more popular in D:OS2 than for D:OS1 for people who like having more of a feel of one primary character with companions rather than four primary characters with separate goals.