"The boss fights are now as they should have been," Emile Pedneault, game designer on the Director's Cut told us today at PAX East. "We took them and completely rebuilt them. We couldn't change [the boss' character] model and the way they need to die because of the story telling, but we changed the level layout. We tweaked their AI and we've added tons of ways to deal with them."
He continued, "You can deal with a boss fight in a stealth way, you can deal with a boss fight in a hacking way. We even have for each boss fight a way to kill them without firing a single bullet."
Pedneault showed us the first boss fight, pointing out all the different ways that it could now be completed using other skills beyond "throw every grenade in your inventory and just keep shooting." There are several corridors now for stealth attacks and turrets for hacking, along with other goodies for players to discover.
The boss fights were widely criticized when Deus Ex: Human Revolution originally launched, with Eidos Montreal eventually admitting it farmed out that portion of the game to an outside developer. Deus Ex DLC "The Missing Link," bundled with the Wii U version, designed in-house at Eidos Montreal gave a far more flexible experience.