I've fought him enraged as I forgot about the change, he began ramming ultra fast and hit me for well over 200 damage, and then I died in about 3 seconds.
I really hope they undo this change, for more than one reason. And before I begin, I have defeated him since 1.3.
First, I disagree with the needing to set up an arena for a battle to be possible, at least on normal mode. The player should be able to win on skill and quick learning on their first try, not be expected to set up an arena, even if it is just simple platforms on the ocean's surface and then again higher up.
Second, there isn't any real indicator that the player isn't allowed to lure him away from the ocean. The first time a player fishes him up, when they see a boss suddenly appear, one of the first things that comes to mind is RUN AWAY! And for doing that they're killed in seconds. They try, try, try again, and are repeatedly killed, not knowing that he remains weaker in the ocean? Players should be able to win without having to check the wiki.
Third, the battle is.. just not as fun this way. Before this change he could be fought entirely at the ocean as well, so this only limits us on how he can be fought. I didn't use asphalt bridges, so I'd still have to kite carefully as he'd easily ram into me without adjusting my vertical speed. I'd still have to watch out for the waves of sharkrons and the cthulunados (when turning around).
He was a challenge for me this way, but a fun challenge. This change.. he's still a challenge, but all the fun is sucked out of the fight for me. Really hope they change it back. At least for Normal.