To be honest there is actually little difference between a BD-Live title and a BonusView or BD-J disc.
All BD-Live adds that is new, is network access. Everything else is just BD-J code. Nearly all players have chosen to not implement persistent storage as built in, but via SD cards or USB expansion, so whether it's 256MB or 1GB doesn't seem to hold much relevance anymore.
A BD-Live player that is not plugged into the network is likely to behave exactly the same as a BonusView player. Interactive network games with no network still won't work.
The biggest problem with BD-Live and to be fair HDi, is not IMO the player code, it's what sits at the other end. Everyone missed the main point here it seems. Universal HD-DVD's required a different (painful) registration process to other studios. It will be the same with BD-Live...
What I think should have been part of the spec was a creation of a BD-Live common network service such as XBox-Live or PSN so that you had one registration and a consistent online experience. Neither HDi or BD-Live seem to have that as part of the specification.
Now, there is nothing to stop the studios getting together and implementing that and then sharing the BD-J code they use to achieve it, but it would look a lot slicker if there was a central service from day one where you could get trailers etc... Hell, they might even be able to sell you downloads through it...
As Sonic points out, although HD-DVD was perceived as finished from day one with respect to specificiation, the network part was not delivered until about 6 months or so after launch via a set of firware updates. It was then constantly updated thereafter. Were they still tweaking HDi?
I think it's just posturing and semantics being used to justify the situation. As Nic has pointed out elsewhere, DVD player updates were quite small, a few MB perhaps, your average HD player update can be 50MB or more.
All Arcam/Denon really needed to say was that the situation wasn't stable enough yet for them to be able to come to market. Just doesn't sound quite so newsworthy.