The package was not really maintained, and twiki’s maintenance still required some attention, as there were quite a lot security issues. So the removal is logical.
I had tried and help maintain it in good shape, but couldn’t do much recently, as we’ve moved a little bit away from its inegration in PicoForge, having other matters to care for in Helios and Coclico these days.
Maybe foswiki (the more open fork of twiki) will enter Debian some day. The ITP is there, and there are unofficial packages to be tested, for those that would need to transition from the previous installations of twiki on Debian. More details in the fowsiki ITP.
Anyway, thanks for all the good work to all those who spent time working on TWiki’s packages in Debian.
As for me, maybe some day, I’ll be interested in contributing some time to Foswiki, should we deploy it alongside FusionForge some day.