The update has clearly fixed many issues .... while its by no means perfect EVERY update has broken jailbreak and/or unlock
Every update is going to make changes to libraries and remap the baseband to make signal processing better (or worse)
The whole pwnage process is based upon FLAWS and loopholes in code ... by its process of continueous improvement these holes will always move .... sure if the hole is blatant (like the TIFF exploit in the early days) then apple will seal the hole .... but at this moment in time ... apple has a bigger problem of making its millions of 2.0 iphones stable and usable before the whole situation decends into a branding nightmare like Vista 😉