I remember the morning the new BBC logo first appeared and I hated it, however I've since come to think its one of the most beautiful and timeless logos around, possibly as powerful in logo terms as the Channel 4 4.
I think the fact it is so simple is often seen as a bad thing whereas in fact it just allows it to fit into pretty much anything. Imagine trying to shoehorn the 1991 logo into the Doctor Who titles, or having it work as those light boxes that keep appearing outside buildings and at events. It just wouldn't work in the same way at all.
I hated it too when it first appeared. While part of that was because I thought the logo looked boring compared to the previous logo, a lot of it was to do with the original branding guidelines which mandated that all BBC logos were to consist simply of the BBC logo with the division name in mixed case Gill Sans or the BBC logo with the channel name in all caps Gill Sans. It made all the BBC's many logos look the same and what's appropriate for BBC Learning Zone isn't really appropriate for BBC Radio 1, for instance. Lambie-Narn said that personality could be conveyed through idents, but that didn't really work in print. Thankfully the BBC ditched that part of the rule book after a few years and while some networks still use all-caps Gill Sans (BBC Four, BBC News) there are many that don't (BBC One, BBC Two, BBC Three).
Personally, I think it all looks a complete mess now.
Every channel and network the BBC have is different, so why should they all be formatted with the same branding exactly?
Fundamentally, they all have the core 'BBC' brand, then that is elaborated with the channel or networks individual brand reflecting its demographic, audience or tone of voice... it works!
You seem to have the mentality that the logo is the most important part of a brand. It isn't, not anymore.
You say, "what's appropriate for Learning Zone wasn't appropriate for Radio 1". You say this as if Learning Zone was using a wacky Radio 1 type font. But it wasn't. They were all using Gill Sans, with a very uniform and coherent identity across the BBC.
The whole point of what Lambie-Nairn did was to save the BBC money. At that point, the BBC was creating two logos every week. We're almost, if not exactly, at that point once again. Every service getting it's own logo or different type of font. It looks like, as chris quite rightly said, a complete mess and not an organisation paid for by a license fee.
The Gill Sans strip logo allowed for the other brand elements to come out. CBBC had its quirky animations, BBC One had the balloon, and BBC Two had (and still has) the 2's. When you think of each brand at the time, do you really think of just the logo, or what is really important - the identity? When you think of Learning Zone, you think of the oak leaves, or just the logo? I could go on.
Each brand has a sufficient identity not to have to depend on the logo. This means that everything looks like it comes from the one organisation, instead of all different ones. No more money has to be spent on new logos, just the identity, and it's easier to apply the logo for different situations, as there doesn't have to be several logo guidelines.
This is obviously a devisive topic, but I personally don't see what's better with the 2-new-logos-every-week concept over the uniform-brand-that-saves-money concept.