Just got off the same cruise and my thoughts are very similar to yours. We booked another Summit cruise for Feb 25 last week while on-board.
Only negative, this made me realize why any cruise less than 9 or 10 days isn't my cup of tea. We did this as it was a better option than what we were planning, but this is the shortest cruise I have ever taken and just left me needing more!! 🙂 🙂