I use bb messenger alot. and I do like the way the iPhone handles text messages. So if texts came up in bbm we'd be able to have threaded convo's that look like im's. Finding that phone number mentioned a bunch of texts ago would be as simple as scrolling up to it.
I mean, they're threaded well enough. most serious BB users are kinda more interested in seeing a nice, strong stable OS build. then we can move onto bells and whistles.
but really? when it comes down to it, we have threaded messages. yeah, some users don't like the format. it's bound to happen. personally, I don't really mind it. if I wanted my texts to look like an IM conversation, I'd probably have the conversation in GChat, AIM or BBM.