It would be great to leverage Power Query Online at scale, as a connector in Power Automate. Data could be retrieved from various sources, such as Excel, CSV files, Dataverse, SQL... (just like dataflows).
Parameters could be passed directly to PowerQuery. (So you could, for example, get a user input from Power Automate and then filter an Excel file in Power Query using that parameter)
Data output would be an Excel or CSV file that could be handled by Power Automate.
Why would you want this? Suppose users need specific on demand information that requires data to be combined and processed from multiple sources, based on user input. The output would be emailed to them as an Excel file.
Now for a pro developer, this might seem like simple stuff, but using existing tools, this is beyond the reach of an advanced Power Automate business users.
Advanced business users often already work well with Power Query in Excel and Power BI. Empowering these business users to use Power Query at scale, in the cloud, would have great potential.