Within a Flow, it would be extremely useful to be able to access the parameters in the initiating trigger for use in later actions or HTTP requests. I originally envisioned this for SharePoint triggers, but it would probably be useful across the board.
Here’s my thinking in a SharePoint context...
When a Flow has a SharePoint trigger, it would be really useful to be able to access the trigger context in the rest of the Flow. For example, if I have a Flow with the trigger When a file is created or modified (properties only), I need to supply the Site Address and Library Name (optionally the Folder and Limit Columns by View). Many times in later actions, I need to supply the Site Address and Library Name again.
If the values I used in the trigger were exposed, I could use them as variables in those actions. Even better, for building modular Flows, I could pass that data into engine-like Flows via HTTP requests which take the Site Address and Library Name as input parameters. Right now,my only options is the try to do some split/substring jiggery-pokery on URLs, which is fragile at best.