I can see where 4e fans are coming in some respects, but not in others.
I'm pretty happy with how 5e is shaping up. It seems to be just the mix of old style B/X and 4e that I like. But even I feel that, while I don't find the L&Ls offensive, they are in many respects boring, vague, and uninformative. The feel very much like the mediocre ones that Monte Cook was putting out. And while I don't share with other 4e fans the feeling that WotC has abandoned the 4e player base and is consciously designing 5e to be the "anti-4e", I can certainly understand frustration that there hasn't been a lot for them, even in terms of promises. My impression is this is because they're very close to getting the core of the core, the "Basic" game locked down. Since Mearls did the big "Basic/Standard/Advanced" breakdown in L&L, his columns have focused pretty much on that Basic game. 2/11 was about how the rules of exploration would be optional, i.e., part of the Standard options, but not an integral part of the game you had to have. 2/18 was about simplifying healing for the Basic game, leaving such things as Hit Dice and alternate rules to Standard options. The articles since then have been vague discussion centered around finding a basic competency for characters, allowing for player-customized specialization, but without making the game too fiddly. While they've been ostensibly about the options that players will have in the Standard game, ultimately what they are really about is establishing a floor for PC competency and complexity that those (as yet unnamed, unspecified) options can build on. Unfortunately, perhaps because Mearls has grown busier as the Basic game nears completion, there's been a drop off in quality and specificity in the L&Ls, meaning not much new information, and not clear indications about what is "corest of the core", vs. what is "core in the sense of available for Standard players with their first purchase of the game".
While it's all well and good, even perfectly understandable, that Mearls might want to focus on the Basic game as it nears completion (the stronger the core is, the better the options that can be added to it), there are a lot of 4e fans who want to see something more than just the classical-type stuff. So what Mearls has to say doesn't really interest them -- they're champing at the bit for at least a look at 4e classes and races. I mean, heck, forget the Warlord, where's the Dragonborn? Surely another race doesn't require the same design effort as a whole new class? The Warlock was pretty 4e-ish, and was pulled backstage to get some work done on it, what's going on with that? Last we heard, magic systems were going to be come swappable, so DMs could go Vancian if they wanted that, or a little more 4e-style if they wanted that. What's going on with that? Where's the tactical module? They seemed pretty far with that late last year, but we haven't heard much about it, let alone seen a playtest version. Given that the latest new classes have been the Monk, Barbarian, and now the Druid, I think it's obvious they're moving from Core Four to Historic Also Starring classes, and the newer classes/races will come later. But even with that, I can understand frustration and impatience.
So it's not just they don't make it totally clear when they're talking about the Basic game, but they're not exactly leavening the Basic talk with any Standard stuff.
(One specific snarl I think that happened is Mearls' thoughts on healing in the core game made a lotta folks fear that the Warlord would not have healing capability, and the push for Warlord info led them to talk about it before they were really ready to introduce it, with the added bonus of seemingly fulfilling some 4e fans' worst fears. One overwhelming feeling I had from the recent podcast is they there's a lot of disagreement and debate among the design team about what a Warlord should look like. 4e fans want a 4e Warlord, but the design team's goal is not to provide straight mechanics and classes from various editions, but recreate the classes so that they are modular. So conceivably a 4e Warlord fan could create a Warlord he was happy with, but at the same time a 3e fan could create a Warlord he was happy with, and a 1e fan could create a Warlord he was happy with. Since there are few prior iterations of the Warlord from which the designers can work from, it's a tough nut to crack, and what they have is not satisfying to some of the designers and/or internal playtesters. Mearls tweeted about where the Warlord is now, but I would not be surprised to see it change before it's finally released for playtesting. Heck, before the Cleric was released it went through a phase where Turn Undead was a higher level spell. At any rate, if Mearls spent a little more time on the L&Ls and gave them a little more specificity, such FUD could at least be mitigated, if not avoided altogether.)
With regard to marketing, I didn't buy it when people said that they denigrated 3e in the run-up to 4e, and I don't buy it that they now doing it with 4e. In any edition change, one of the things they have to do is note what was found problematic with the previous edition, and how they are trying to fix it in the new one. Otherwise, why put out a new edition at all? Now, one natural outcome of that is the Gnome Effect. A seemingly slam dunk decision creates a huge backlash. Let's say that 4e players represent 50% of the D&D playing population that might conceivably move on to Next, 3.x/Pathfinder players make up 35%, and TSR-D&D players make up 15% (just to pull numbers out of a hat). Now let's look at 4e powers and assume that the 3.x/PF and the TSR players don't care about 4e powers, and that half of the 4e population are perfectly fine with an alternate system as long as they can still get the same feel as from their 4e games. That's 75% of the base if lose 4e powers vs. 50% if you keep them. That's a no brainer! But that 25% is going to be pissed, they are going to be vocal, and because D&D is played in groups rather than as individuals, that's going to have a disproportionate effect. And I'm not trying to pick on 4e or 4e fans here. The same was true in the change over to 3e, and in the change over to 4e.
Then there's this. Go into any rpg forum and ask "What's better? Moldvay Basic or Mentzer Basic?" The rules are virtually the same. But it won't be long before a Moldvay fan puts down Elmore art, or a Mentzer fan puts down Otus art, or respective layouts, or even notes the differences on the "Ages 10 & Up" notices. Yes, when the rules are the same, people will Edition War about presentation. Dragonsfoot even has separate forums for its Classic D&D, First Ed. AD&D, and 2nd Edition. Because even if you remove WotC D&D entirely from the discussion, people will still Edition War. If people identify with one edition over others, it's just human nature to desire to trumpet its merits, and likewise to take criticisms of it personally.
WotC has exacerbated this with its (mistaken, in hindsight) strategy of completely renovating the game every edition. I don't necessarily blame them; there were good reasons for each renovation at the time. But they've put themselves in a tough spot. But personally, I think they are doing what is perhaps the most sensible thing. Provide every edition for all of the die-hard hold-outs. Then for those who aren't die-hard, provide a variable-ruleset system that can emulate aspects of the other editions. Avail yourself of the history of support. Use the emulative qualities of the new edition to provide support for the older ones. It's the
bucket theory all over again. TSR went through the expense of making too many separate buckets to catch all the raining money. With 3e they chose to kick those buckets over and make one big bucket. Then with 4e they kicked that bucket over and made a smaller big bucket. With 5e they're trying to make another big bucket to go with that one, and at the same time right all the buckets they previously kicked over.