Thanks a lot for your feedback.
You can focus the library's search box using Ctrl-F, but sure you still have to drag'n'drop the node. Showing the library as a popup to directly add nodes (either with a shortcut or when connecting an output to empty space in the graph view) is somewhere on the roadmap. ;)
About parameters, would you like to have them as inputs ? And have math nodes to build expressions for those parameters ? I think this is too complicated and I cannot find a good reason for that. Please don't hesitate to describe a use case so I can think about how to solve it.