Gustaf, taking your posting, please make a TIP so we adopt xotcl along with the already approved TCLLIB in 5.3 and the 5.3 documentation. I think you have provided enough arguments for the OCT to make a decision on whether to adopt it (and make use of your calendar).
One major issue though is the additional learning curve that comes with xoTCL enabled code. I personally don't mind and I think this might even make OpenACS yet more attractive to other developers, but nevertheless, it is more to learn and OpenACS is already difficult to pick up in the first place.
When you write the TIP, maybe you can share some more of your enhancements or ideas for enhancement where it would make sense to switch to xoTCL instead or in addition to the functionality we use within OpenACS (after all, we are somewhat oo-ish in our code anyway).
