If you have Steam, Secret World Legends is integrated into it. However, if you already have an existing Patron account for Secret World Legends, don’t link it yet. They’re having integration issues tonight.
As for Whispering Tide: I’ve been looking forward to doing this one for a while. When I started playing The Secret World, they had just begun to wrap up that particular event, and I missed it. I’ve wanted to play it ever since. Gonna be fun!
The differences between the raid for the event, and the TSW bird raid are interesting, but understandable (never ran it in TSW myself, but read up on it on the Reddit). In fact, the first time I ran the event, I didn’t even realize that a mini-boss was spawning on the upper platform (found my way up there after getting knocked off, but I noticed today that the mini-boss dies almost instantly from just a few people). I spotted a Whispering Tide lor… er legend (#6, iirc) on the entry ramp that wasn’t there yesterday. So keep an eye out for it if you don’t have it. Haven’t seen any others yet, so I don’t know if they’re going to throw them in one a day, or add them in later when the Venice and Tokyo portals open up.