No pre booking required on Arcadia. Have heard no complaints about full venues. Unlike Iona and Arvia. The venues seem to cope with the amount of pax on board, as they always have done.
Hate being organized on holiday. Prefer spontaneous decisions about what I want to do, and when. Hence sticking to the smaller ships. Whatever floats your boat though! I do like a cocktail though!
I am not loaded, just done many cruises to qualify for Ligurian tier, all in balcony. However, some can attain that level just cruising in cheap interior cabins, not necessarily loaded.
Personal opinion, but have done over 70 cruises solo and small ships are much more sociable. However, much more expensive particularly if you want a balcony. Also depends on your age as small ships have a much older demographic!