Most multiplatform games will be late ports, unless they're small scale indie games. A game of the scope of Doom or Wolfenstein will always be a late port because most developers aren't willing to delay their PS4/X1 releases just to launch at the same date as the Switch version, which needs more time to make work on it.
It doesn't take more time to make it work. At least with scalable engines like Unreal etc. The issue is, the porting began when development was almost over. Thus, the late releases on Nintendo Switch.
Therefore, provided 3rd parties want to actually support the system, they can release simultaneously with other platforms, without delaying their games. That said, I have learned not to trust PR talk, and especially Reggie.
I think we'll not see a huge flock of AAA 3rd parties to the Switch, and I'm fine with that. As long as I have my Bloodstained, Shin Megami Tensei, Octopath and other AA, I'm more than happy.
Making a AAA game work on Switch requires much more than porting. In the case of Doom they had a hard time optimizing for such weak hardware, and Doom isn't exactly the most technically ambitious game either.
Doom was ported by a seperate studio.. why? Id Software managed PS4/X1 and PC, why not one more platform? Because it was busy work. So when they get to making new games, like for example Doom Eternal, they make it for the PS4/X1 as the base line because tethering their game to the Switch would be too limiting. Switch is the outliar and requires developers to go out of their way not just hardware wise, but rendering wise. This is the main reason Switch versions come late, or don't come at all.
Seriously, this AAA third party support for Switch is theatrics. There's only so many 300k selling frankenstein ports these publishers will tolerate before calling it quits. Switch is better off getting games made for it's strengths instead of basterdized PS4 games that don't play well. Like you said Bloodstained, Shin Megami Tensei, Octopath are all AA third party stuff made especially for Switch. That stuff will prove to be Switch's biggest asset, along with it's first party stuff of course.