We just got back from our 3rd cruise on the Oasis of the Seas, and as always, it was terrific. I have another booked to do Western and Eastern Caribbean back to back next April 2016.
I've read a few negative reviews on here about the Oasis, and while I can't totally disagree with some of the negative points, for example; the crowds or the Windjammer specifically, I know for a fact that most of these issues can be avoided.
Yes, on Day 1 walking onto the ship, if you hang out on the Royal Promenade, it's crowded. That's the entry point onto the ship, and the first place the gawkers stop to take photos. Easy fix - avoid it. Keep walking and get out of the press of people. Take pictures of it and explore later. Everyone that isn't on the Promenade is at the Windjammer. Stay away unless you want to eat standing up. If you're prepared in advance you can hit Central park for a quick drink, a snack at the Park Café, and if you have your swim suit, you can hit the hot tubs overlooking the edge of the ship, have them to yourself, and be 3 drinks in and forgetting about work by the time everyone else is stumbling off the promenade to see if their room is made up.