All those things you mention are design choices. Perhaps one of the impediments to the development of new user agents is a feeling that they must be complex an

All those things you mention are design choices. Perhaps one of the impediments to the development of new user agents is a feeling that they must be complex and meet some "standard" of features. A standard that is nigh impossible to meet for the average programmer. On top of that, web developers demand the ability to create complex web pages full of executable code. However we have no proof that users would reject a cornucopia of different agents that did not all have the same set of features. User agents do not need to be designed to satisy web developers. User agents can be designed to satisfy users. They can be designed to do one thing well instead of do everything. No user agent need be intended to "replace" any other, and certainly not to replace "modern" browsers. The intent is to create choice and user experimentation. It is still possible to access the web with simple programs. It is not gopher or gemini but it still can work in a relatively simple way. Web developers probably do not like that but it remains true. The complexity of today's web sites is optional. It is a deisgn choice. Made possible by... "modern" browsers. Godspeed.