tentative fullpath loading is already supported if the user changes the extension to .lyx
maybe no-intro should change extension to their dumps, but extending the heuristics to the format .lnx, which was created to use the header information, is not really a solution IMHO
Just add a check for the header and treat it as .lyx if one isn't present. We need to meet common use cases in the middle, and this seems like a simple and obvious one.
Put another way: this user wants to actually use a non-arcade driver and you're trying to drive them away to Handy instead. That's bad for the project, especially considering how simple the necessary code change is.