While the whole re(re,re,re,re-)litigation on 4e is fine and all, I find this part more interesting.
How big is WotC D&D segment? How many staff? How is it possible there are these 'warring factions'? Is it C-level vs Designers? Is it Design Management vs Individual Contributors?
5e is a fence sitter of an edition. Its not saying anything too bold, and it certainly is trying to appeal to 'everyone' while appealing less to any one, and I would have assumed that was the intent.
I have to wonder what direction these assumed different factions actually want to go in.
You can get a sense of the size of the team from the credits page of any recent 5e book. A lot of those credits are for artists or production folks, like the people who actually do layout for the physical books. The design team itself, the people who design the game, is probably...fifteen-ish?
Is it C-Level vs. Designers or Design Management vs. Individual Contributors? Both.
The key, as always, is not to ask how many designers there are, but
who those designers are. Only two or three people currently designing 5e were on the team when 5e was launched: Crawford and Perkins. (I think Wyatt was there at launch, but left for much of 5e before recently returning.) They've been around a long time; Perkins since the TSR days, I think. If anyone's had the chance to create organizational or political power, it's those two. And yet they keep getting passed over for promotion to the top jobs in the D&D segment. Each time there's an opening in senior D&D management, someone is put in charge of Crawford and Perkins. Mearls was their boss for most of 5e's initial run. He left and Winniger took over. Now Winniger's out and Kyle Brink's the boss now, with Dan Rawson, the former Amazon and Microsoft executives, as Brink's boss. After Mearls left, what's been consistent is that the C-Level people (the people above Winniger/Brink) have put people who are largely non-game-designers in charge of D&D. Even when Mearls was in charge of D&D's design, Nathan Stewart was his boss. Nathan Stewart is a marketing guy. As you go from Mearls -> Winniger -> Brinks, the line on the graph of game design experience goes down practically logarithmically.
So is there factionalism between the C-Suite and the Designers? Probably, but likely in the Don Draper "I don't think of you at all" sort of way. It's clear that the C-Suite doesn't really care about the design of the game itself. If it did, it would install leaders who understand the game and its history. (o choose the right leaders, though, the C-Suite itself would have to know what to look for. They clearly do not and are taking advice from horrible sources. The OGL fiasco should make it clear that they don't. I think the C-Suite, including Rawson and probably Brinks to some extent, sees D&D as an Asset to be Exploited. There's friction with the Designers because they know the Designers are naughty word up, but they don't understand the game or the market, so they can't figure out how to fix it. But they've been charged to fix it and to make the numbers go up. So they get frustrated and factionalism begins.
What about Design Management vs. Individual Contributors? Again, let's focus on actual people. "Design Management" means Crawford and Perkins. They seem to be the front-line managers of the D&D design team. As I mention above, they've been around a long time. There have been big changes in the D&D design team over the past couple of years. They've probably hired almost everyone that's currently on the team. All that said, some freelancers have gone public with their negative experiences working with the D&D team, including one complaint of credit being taken for a freelancer's ideas. There's the the recent controversy with the hadozee in
Spelljammer that certainly echoes the 4e anecdote in the OP about someone jacking up monster hp just prior to publication. I get a real "TV showrunner" vibe from Crawford and Perkins, but the negative version of that stereotype that portrays showrunners rewriting every script and taking the lion's share of credit behind the scenes. Does that produce factionalism? It might. There could be a group of junior D&D designers who want to align themselves with the powerful "showrunners" and others who think things should be run differently. I listen to too many TV writers' podcasts, though, so there's probably some bias and framing creeping in.