Query parameters are a very important element of creating interactive & dynamic apps. Many times, I'm using id={{item.id}} when opening another app.
Right now, there are some things that should & could be better:

• Query params are not accessible to queries on page load. If I want to use query params to load data, I need to work around this issue with a data responder. See the attached app for an example: Query param page load issue(1).json
• Query params should persist on mode switch (at least from edit to preview mode; maybe even edit to publish mode). This may seem like a convenience feature but on an app that uses query params, having to go to the url bar and adding the query params everytime I preview an app is very annyoing.
• Make query params editing a ui feature. Maybe even let the user set default params for the edit mode. Definitely a convenience feature but it may also set the stage for making query params more accessible to less technical people.