Take any open source application and ask around if the code is good, is modular, scaleable, etc. Someone will always find something to complain about. "critique" is very easy.
The question should be:
Does it work or not?
Does it solve my needs for now and the foreseeable future?
Most people use Tiki without changing any code. So code structure/philosophy is of no importance to them. They just want something that works and something which they can upgrade easily over time.
For people that do get involved in development, they want a friendly place, access to other people to bounce ideas & ask for some help. Most of them also want to be able to contribute back. Here is an introductory documentation for developers:
170+ people have committed at least a line of code to Tiki. And countless others have helped with tech support, testing, documentation, etc. So somewhere, somehow, they thought it was a worthy enough project.
For many years, I have read criticisms / concerns / etc about Tiki design. It won't scale, it will implode, etc, There was a lot of FUD:
However, here we are. Tiki is 4 years old. It's a mature, very powerful application, with a large community of contributors, with tons of features and which is used on tens of thousands of websites & Intranets.
Of course, there are a lot of things to improve and there will always be. Please see:
to see if Tiki is a good application for your needs. Remember: if you don't need a feature, don't activate it. However, if you need it in the future, it's only a few clicks away.
And remember also, Tiki is open source and open development. YOU can participate to its future.