The registry hack is not something new, it used to be 2 parter - Disables the Nagle algorithm (which Blizzard has already patched in dunno how many years back) and the TcpAckFrequency. The latter is client side so Blizzard cannot do anything about it. Basically just tells your Windows to wait how long before replying. Default is 2, but it's recommended to change to 1 (min value) for latency sensitive games like WoW.

I'm not sure about the rest of you, but my gripe with TMnet nowadays is not about the latency, but the bandwidth. And only to certain networks (unfortunately WoW server is one of them). What happens is, I ping and get very nice latency, only 200ms or so. In-game it's about 400ms. But I couldn't log when my toon is in Dalaran at all. I can play 5-men fine, but 25-men is DC hell. This all points to bandwidth and not latency issue.

I tested with speednet, bandwidth to LA is around 100kb/s, but bandwidth to San Diego is only a mere 3kb/s or so. I'm not sure where WoW servers are located (I thought it's LA), but this kinda prove that TMnet is utilising some sort of selective bandwidth to servers. This also explains why my Rapidshare downloads are going super slow on certain servers but super fast on others.

Oh, I have a confession. I use GearScore as well.
I'll make sure to turn it off when raid starts if got ppl DC. (IMO GS is still useful if you're Pugging, always safer to have a 5k GS nub than a 3k GS nub, and no way I'm going to run ToC10 with 5 3k GS nub no matter if they've killed Algalon on their mains... There's still this thing called Gear Check!)