there where changes from 2009.2 to january this year but in this moment there is no changes because the 2010 release abandons kde3 and uses kde4
pclinux is smooth with updates but many users were concerned because new updates could damage apps in kde3 because many developers abandoned kde3 and adopted kde4, as you know some libraries are shared by gnome and other desktops so it is hard to update something without damaging something else
kde3 had its last update in june last year and the last security fix in october
to make the transition more easier for all the pclinux users, the new iso will require to reinstall the system to avoid broken installations
kde4 represent for many users a big step, for others a break point, it is a very interesting and unique moment for pclinux
you say you can't brag about smooth pclinux updates but go from kde3 to kde4 is comparable to update windows xp to vista with a service pack downloaded via update manager, a little dangerous don't you think?
too many changes to do it this way and remain safe for every person
some of us did a test install of kde 4.3.4, for some users it went very well, others had panic attack because the results were not what they expected

it is a big step that requires patience to do it well