With the introduction of C3P0, there will be more and more people solo'ing the HAAT raid. The Pit raid is already in this situation where you solo it and come in position 30, etc.
With so much in the game, these are extra things that you have to do and make sure you are online at a specific time to participate.
For a QOL improvement, what about during the join phase to add a "Join" button (like it works now) and a "Solo" button which is available only if you have solo'd that raid at least X times (maybe 10 or so).
If you press that, you will join the raid and will automatically get a solo score at the end of the raid. If by the time the raid starts there are only solo joiners, the raid ends immediately and everyone gets a solo score. The rewards can be paid out as before.
This allows you to have the option of actually battling the raid or still being able to get in there as a solo poster.
I'm hoping any future raids won't require people to have to be on at a specific time of day. The GA and TB where you can complete it at-will is really awesome.