Based on what I've seen so far of the new PHB, I think there are slight changes that are going to have a big long-term impact on how players engage with the game. I believe one impact will be players thinking "Class first, background and story second."
I'm not sure that's true. I think you can start with a background and build from there just as easily.
Let's try: with Sailor as an example.
Everything that's in the feat makes sense for someone who has spent time at sea (given the level of granularity D&D offers). and from it, and looking at skills and ability scores, I can see it being great background for optimizing fighter, rogue, druid, ranger, and viable for cleric and maybe valor bard. All those class choices emerge from the background, I think, well, and are supported. Stating with the background lets those concepts emerge and be supported. And you always have the nautical feel with the navigator's tools and tavern brawler.
Now, I can cavil at the choice of Acrobatics rather than Athletics (maybe allowing a choice of two of three skills for each would allow a bit more flexibility), but I'm not going to worry about that.
I can also say, but hey, my character was a sailor but he never got into fistffights. He's officer material. And if that's the case, I can always take the noble background and reflavour it as Naval officer and no need to change anything else.
finally, as the video points out, Now I wouldn't have thought of becoming a monk if I had started with the sailor background, but it works well.
All that's to say, I don't think there's any reason why you shouldn't or couldn't start with backgrounds, and you might build something that is fun and narrativly tight.
And the same goes for species, but I think that if you want to start with species: if I want an orc cleric, say, I might make tactical choices on the background I select in order to get a feat that works for what I'm imagining. And in doing so, I might end up with a skill that I wouldn't otherwise have chosen for myself -- so at a quick glance for an orc cleric, I might choose farmer (if I want tough -- suddenly I have animal handling! cool and unexpected), or guard (because I want the athletics proficiency, which I'm not otherwise getting from cleric, which suddenly means I also get alert.
All that's to say, I think the system is working as intended, and not actually offering the straightjacket that it might seem.
The combination of presenting the Class chapter first, and also attaching ability score boosts to Backgrounds... I think that's going to reinforce that trend, and also sway some players to the "Class first, background and story second" mode of thinking.
I think that' true, and this will help new players, since the class is what changes most over the course of play.
I don't think it's locked in, though, by any means.
