"My comments were generally rebuffed by LL staff at office hours as they were against the pure ethos of SL itself as a live streamed world."
Hmm, well never underestimate the Lindens' ability to underestimate the difficulties users have with their product. But I'm not sure live streaming is really an ethos. There's an ethos of user-generated content, to be sure, but live streaming is more a technical architecture than an ethos. And while it enables some nice things, preloading wouldn't replace it. Really I'd just be supplementing it with what amounts to more intelligent caching.
I think it goes beyond the new user experience. I rarely log in anymore, but even when I was a regular user I spent 90% of my time in fewer than a dozen sims. My experience would have been improved if I'd had a way of "subscribing" to them and having their content kept up to date automatically, maybe even offline while the SL client wasn't even running.