Out of sheer curiosity I've attempted a "crude" comparison of the current versions used in the tool chain for TC 2.x and TC 3.x. For this I just used the URLs of the sources mentioned in the .info files of the dependencies of compile.tcz. There is therefore the (theoretical) risk that my findings are incorrect, since I have not tried to check the "real" executables and libraries.
Please note I'm writing this here to gain a better understanding of how the whole change from TC 2.x to TC 3.x takes place and what might be still on the horizon. Overall I'm certainly quite impressed how well TC 3.0alpha is shaping up.
What I did was that (actually a few days ago) I simply "followed" the URLs and checked if a newer version of a source tar-ball seemed to be available (either in the same directory or somewhere in the "neighborhood"). This is probably not the best heuristic, but as I wrote before I'm just a bit curious without having any particular intention. In a few cases the URLs appeared to be "stale", so I used "google" in an attempt to find the most likely "current place".
Most of the extensions in question have been "bumped up", but for some (like flex, make, and pkg-config) TC 2.x probably has already used the latest available version. Then there are some which appear to be now on the latest available version (like bison, findutils, gmp, m4, mpfr, patch, ppl, and sed). For a few (like binutils, cloog, diffutils, file, gawk, gcc, gperf and grep) a newer release seems to be available. But since in almost all cases this appears to be just a slightly higher minor version. I therefore consider the tool chain to be pretty much "up to date".
I've only "stumbled" over a few small things where I'd appreciate if someone from the Core team could maybe share some insights:
(1) Judging from the URLs in 'base-dev.tcz' the libraries have by and large not been changed (apart of course from those related to the kernel, gcc and glibc). There appears to be in some cases (like libfltk, libjpeg, libpng, ncurses, util-linux and zlib) newer versions available. Is it under consideration to include some updates of those in the future?
(2) In TC 3.x the 'gcc.tcz' extension has now dependencies (i.e. 'cloog.tcz', 'ppl.tcz', 'gmp.tcz' and 'mpfr.tcz') which were not required for TC 2.x. I'm curious to find out what the advantage for the "average user" might be in including those now. In particular 'ppl.tcz' with it's not exactly small size of 4.4MB might be of interest here.