On my 2 cruises I have seen first hand how hard it is for single cruise hosts for the travel agencies to organized events for the single guests. One thing I notice that almost everyone has an agenda either to hook up, go on their own or socializing with other guests. I agree the main problem is complaints about the rooming situation even the single host room with one of the guests.
The hosts has to be all things to all people and has to deal with every single cruise guest moods for day to day which could be joyest one day to grumpy another. If you are organized and like to mingle with various people I say "Go for it!!!"
I have been asked by several of the singles cruise agencies to help host a singles cruise. I tried it once many years ago and said never again. It was just way too much work, way too much responsibility; however, every host or hostess, coordinator--call them what you will--that I have met said they loved their job, so I guess for some people it is the ideal career. I would rather just go on the cruises and write about them.