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.

This is what Reggie always says, he said the same thing for 4 years about the Wii U. No, I'm not saying this is the same, but Reggie talks, it's his job. Let's see the games, Reggie's words alone are uninteresting as they've proven hollow many times before.

Yaaay more ports instead of new games..

They dont talk about ports of old games, they talk how games coming later to Switch compared to PS4/XB1 and Reggie said how gap between releases on PS4/XB1 and Switch will be closed (from end this/next year), that games will not be released later on Switch any more like we saw with Wolfenstein 2 and Fortnite for instance. 

This is somewhat consistent with an interview to Nintendo of France where the rep said they are most lileñy going to continue announcing games during July, August and Sep events. Hype!

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.