We sailed the Sun in October of last year. I posted a review that was fairly thorough as I recall. Hurricane season will be over by December so that shouldn't concern you.
The Sun is a great ship. There will not be the glitz or neon you may be accustomed to on Carnival nor will there be dancing waiters or red, white and blue competitions. All plusses from my perspective. Freestyle is a great way to go for dining, especially when you've gotten back from a late excursion or want to be railside for sail away which might be during your dinner seating.
We found security to be good. I've forgotten the particulars now but I do know there was an incident with a rough and roudy cruiser and she was nicely warned and when her behavior persisted she spent the night in the brig. The seemed pretty no nonsense about security - which is as it should be.
I think you'll enjoy your time on the Sun. Any particulars, just ask.