I agree with you but it doesnt come from the event itself.
It is a raid event. Boss arent supposed to be fight alone.
Both issue you're talking about comes from the fact that ppl don't join raids. You can clearly see how it is intended to work during ragnarok boss fight, which is way easier and faster in the end.
I don't know how it could be fixed. Active union can help (ppl from your union will more likely join the boss you're hosting), but to be effective, it should prioritize union member request (request are a complete mess actually)
And i think i read somewhere that expert boss will only cost 2 bp to join in the future. So more ppl will be able to help others.