Just a quick suggestion about a change in logic for the last.fm plugin... Either through an option or just through normal behavior when the "Reattempt failed submissions" option is enabled...
Change / Make available the option to have the plugin basically only reattempt the earliest failed submission until it finally succeeds, then move onto the rest of the "queued failed attempts", in the order which they were played.
In just starting to use this plugin, I have watched how it tries to resubmit failed attempts, but the way it currently processed them, it's anyone's guess which one out of the failed ones will actually succeed first. This causes last.fm to then ignore any submissions with a play date earlier than the one that finally succeeded.
Take this example... I play the following tracks in the following order:
Track 1
Track 2
Track 3
Track 4
They all fail submission and the plugin continues to retry, such as this:
Submit Track 1
Submit Track 2
Submit Track 3
Submit Track 4
Submit Track 1
Submit Track 2
...and so on...
Then, all the sudden, it submits Track 4 and it succeeds. Next it goes back to Track 1 again, but Tracks 1-3 all get ignored by last.fm, because they were played earlier than the last submission.
Instead, if there is a failed attempt, stop at that attempt and kept retrying only that attempt (let the rest just "queue"). So, in this example, the plugin would continue to try to submit Track 1 over and over until it finally succeeds, then tries the next in the order played.
Just a suggestion... Not sure if it had been mentioned before. I just noticed all of mine have been failing for the last 20 minutes or so (last.fm maybe having problems).