I really loved using the old !fast and !expert assistants. Unfortunately I don't have the prompting skill to recreate these assistants - and I don't really care to research that right now. So the new assistant is somewhat of a downgrade functionality-wise for me.
Kagi should provide more Default Assistants for a variety of use cases; just like we still have the Code assistant available.
Users should also be able to extend these assistants with additional instructions. The settings page indicates this is possible but I don't think it is:
These Assistants are created by Kagi to provide special functionality, or get you started with creating your own.
When starting a conversation, users could pick eg Fast Research Assistant as the "model". This could also be accessed with a custom bang.
When creating a new custom assistant, there would be an option to select a specific Default Assistant as the base; with the custom instructions being added to that base system prompt. Users would be able to go back and change what base is used by editing the assistant settings again.
For example, I could create a Fast Research Assistant to help me research healthy food choices; I would tell it my dietary restrictions and taste preferences, but wouldn't need to specify how to cite sources etc. Then decide that the Fast base was not what I wanted, and convert it to an Expert base.