Not all the bosses are nuts but some are. I haven't seen anything in FFXIV that compares to, say, Yogg-Saron, the Lich King, Hellscream or even Blackhand. I'm not saying I want FFXIV to be WoW, of course... WoW has good (sometimes excellent) gameplay backed by awful, awful, content (if any content). That's not at all what I want to see for FFXIV but Yoshi P says he draws inspiration from WoW. WoW's approach to encounter design is its best feature and currently its one remaining GOOD feature.
(No seriously don't make FFXIV a WoW clone that game is a sad, sad mess)
I admit some of this stems from selfishness. More dynamic bosses might mean more spectacle. WoW bosses have some great spectacle moments like falling through the floor on Blackhand or Yogg-Saron's Braincase or flying on Alysrazor... Even Madness of Deathwing was a spectacle though it was not a very good or interesting fight otherwise. If any franchise could knock it out of the park in terms of spectacle moments or being generally outrageous it's Final Fantasy. You know, the series that brought us, amongst other things, insanity like Lady Yunalesca, Kefka, and honestly others too numerous to list (Omega, Ultima, Yiazmat, Sephiroth...)
Primal battles can be intriguing but apparently we are moving away from them? Don't quote me on that