suz wrote:I'd actually worry if the opposite happens. Every random bum waiting in town to join
your particular party? And endlessly waiting for you to speak to them? Nope, not suspicious at all.

I hear your point. I think it is a given that everyone hate cardboard characters that only wait for you to "click" them. I think part of the problem can be contributed to the way/game mechanic party interaction is handled. In Ultima of old and much of Baldur's Gate, one literally have to talk to the companions. What I am saying is that I am more for the companions reacting to what is going on in the player's particular play path. And some of the reaction can/may include initiating some other quest but these quests should not be the primary source of "loyalty".
eg. In Planescape: Torment, the player have a chance to look at the tattoos on the Nameless One's (PC) backside by interacting with a few in game objects. And one of the Tatoo reads, "do not trust the skull" which directly refers to the first companion you get, Morte the floating skull. This enable the choice for the player to challenge Morte about it, which of course can turn into a big argument. Morte would hit back with how crazy the PC can get in his previous incarnations but with the right stats check (was it wisdom or intelligence? not sure), the PC would have some flash back of how his previous incarnations had abuse Morte and take note that Morte still stay with him despite of everything. He then realise (don't remember if there is another stat check) that Morte genuinely feel sorry for him. I think you have the option to apologize to Morte and it actually improve Morte loyalty and other stats.
There is not any sidequest, just great dialog as a side effect of something else you did in the main plot. Granted, the play mechanic was limited by the game engine in the sense that yes, you still have to talk to Morte after the discovery of the tatoo. But after almost 15 years, I gathered the developers can improve on that.