So, sorry, "I don't like DB and they're in 4e so they're unpopular crap that should be dropped" is just the worst kind 'reasoning' there is.
I agree with you, but I still don't want them in the first players handbook.
I think that's what people are forgetting here. You can't fit everything in the first book. Unless you make it like say, The Encyclopaedia Britannica 'book'.
I love devas and dragonborn, even if they did take a while to grow on me. But I don't want them right at the start. They always felt like really rare races to me. Common races need to be available first. The same applies to tieflings.
We all have to bear in mind that somethings will not be available at the start - It just can't be done. SOMETHING has to be left out. It is logical therefore to leave out the things which appear in the fewest editions. Devas and Avengers only appeared in 4E, and even there they weren't in the first PH.
The community is a bit too focused on the extremities right now. WotC are trying to unite a very large group of disparate people. That's no easy task, especially when 4E put many of those people in a very anti-WotC mindset. We, and they, need to focus on the actual core of the game first. Whether devas or avengers play a big part in your games or not is not a criterion for putting them in the initial release on 5E. If they play a big part in EVERYONE's games, then we need to look at it.
2E started with 6 races. 3E started with 7. 4E started with 8. If 5E continues the trend and starts with 9, that's still only a very small portion of the available player races we've seen across all editions. People get too caught up in forming an opinion on an edition before it is 'complete'. The first 3 books simply cannot contain everything. The sooner we accept that the better. There is really no point in judging 5E by the races we see in PH1.
Also, please bear in mind that some of the things people are picking up on are just random thoughts thrown out by the developers - they haven't categorically said avengers would be a theme, they just suggested it as an option.
To me personally, having a deva soul in a reincarnated body as a theme make perfect sense. That doesn't mean this is the option they will go with though.
As for Avengers, I always saw them as an alternative to paladins. Turning them into a kit or prestige class or some other variant form of paladin makes perfect sense to me. If that's called a 'theme' now, then so be it.
Every edition of DND takes common English words and twists them a bit. In this instance it looks like theme is going to be one of those words. From what we've heard thus far (which is very little!) 5E theme is very different from 4E theme.