I have sailed multiple ships in the Fantasy class, Paradise included (back in '03 when it was still no smoking). Due to this, I knew going in how this ship would compare to newer offerings from Carnival and competing lines.
First of all if you are capable of "making your own fun" you will probably have a good time on this boat. I started cruising in '95 (I was 21 then), so I'm familiar with the activities boats of this size typically offer. If you are content with the pool deck, casino, meals, comedians, and maybe a show or two you should be fine. If all you know is Carnival Fun Ship 2.0 (upgrade) boats (or RCCL for that matter) the Paradise may seem kind of boring.
-Lido deck restaurants (outside or inside, including the deli and pizza) were always nuts. It seemed like 10 minute lines for at least an hour (sometimes more) during both breakfast and lunch. I only ate in the MDR during the day once (lunch), and it wasn't busy at all. It appears that the people on this boat prefer the buffet meals. Dinner (buffet) selection was very poor during the one evening I checked it out, although (again) this may be typical on this ship.
-Yes the interior looks dated. No way to hide this given that you enter the boat and the first thing you see is the atrium (which looks as dated as anything on the boat).
-Stateroom looked dated as well, and had a "yellowed" robe, but served its purpose as a comfy place to sleep.
-MDR (we had my time dining) hostess didn't know the show schedule, as was surprised when they got crushed immediately after the show. Service was VERY slow that night. This was surprising as it isn't like they don't go through this every few days.
-Seemed like the pool deck bars were understaffed. One bartender for a ~10 seat bar for extended periods of time. They were pushing buckets of beer hard, I assume this helps relieve the pressure some.
-MDR food was average. Not necessarily a con, but as someone who has been on 9 Carnival cruises in 16 years the gradual decline is something I can't help but notice.
-Stop with the bacon police. It only backs up the buffet lines even more. I'm sorry that people waste a bunch of food (sad really), but add $1-2 to everyone's fare and let people grab their own bacon. Deserts I get (they are separate anyway), but the primary buffet lines really need to move faster.
-Less than $90/person/day (family of 3, not including tips). Cons aside, I felt that I got what I paid for.
-Serenity deck + waterslide are a nice touch for this older boat.
-Pool deck (pools, deck, chairs), while worn, was in good shape.
-Bed was really comfy.
In my opinion, if you have complained about Carnival in the past you will likely do so again if you sail on this ship. In addition, if you are familiar with the Fantasy class ships nothing on this boat should surprise you. If all you care about is some food, the casino, the pool, alcohol, a few ports here and there, this boat will do. If you want more, you need to pay more.