The Imagination is a Fantasy Class Ship, they are laid out so that the bottom 4 decks are for staterooms, and the higher decks are for pubic areas and entertaimnent. The exception is Veranda Deck - they have Cat11 Suites and inside staterooms.
If you are simply looking for an ocien view room, the best deck to be on is Empress. That is where you board and disembark the ship at the bginning and end of the cruise. There is also less walking up and down stairs or elivators, the restaurants are 1 deck above you, you are on the same desk as the purser's office.
If you have a room at the back of the ship, you will notice more vibration from the engines.
The Advantage of a Cat11 suite - go down the hall and you are outside on deck, the pools are only one deck down
There is also another category of ocean view called a Cat 5A - these have 2 smaller porthole windows and are found at the very front of the ship
hope this helps