175,000 people were allegedly happy to helped be experimented on with testing for DDN!
Sure, but they signed up for it. The DDN playtest was explicitly described as a playtest: These rules are a work in progress, they're going to change, and you get to provide input into those changes. Also, we aren't charging for 'em. 4E was presented as a finished game and sold for money. I saw a whole lot of complaints about that.
Anyway, my personal experience of 4E, with background:
I started gaming back in the late '80s. I cut my teeth on the Red Box and progressed from there to 2E. My GMing and playing style were thus shaped by editions which relied enormously on the DM making stuff up on the fly. I kept that style through most of 3E, even though it wasn't always the best fit. When players complained about things like me not following the WBL guidelines (the best 2E DM I ever played under was notorious for campaigns where characters at level 10+ didn't have two copper pieces to rub together), I grudgingly adjusted, but it never sat well. The more I played and ran 3E, the more I felt the "weight" of the system.
I also did a
lot of fudging. As DM, I tend to focus on lengthy plot arcs and narratives, which work best with a stable cast of PCs. But I also don't like easy resurrection, which plays havoc with world-building in my view. Since easy resurrection has historically been D&D's way of enabling a stable PC cast, fudging was the only way I could accomplish both of my goals. In BD&D and 2E, this didn't bother me; I was making up so much stuff on the fly anyway that fudging a monster attack or adjusting monster hit points was just more of the same. But in 3E, with its heavier and more coherent rules framework, the necessity started to annoy me. I also became acquainted with the joys of DMing for high-level casters*.
4E promised to make my life as DM vastly easier; making characters more durable so I wouldn't have to constantly intervene to keep them alive, reducing the need for magical treasure, making it possible to easily create spectacular set-piece battles, and cutting back the ability of wizards to derail adventures. I was excited about all these things, and I have to say that 4E delivered on its promises. The first year or so of 4E were awesome. I ran one of the best campaigns of my life, which my players and I still remember fondly five years later.
However, the more I played and ran 4E, the more its limitations started to grate on me. Yes, it made it possible for me to create spectacular, engaging, tactically rich combats--but it was a substantial amount of work to design those combats, and I had to do it
every single time. If I tried to improvise an encounter, it usually turned out boring and grindy. Furthermore, as the players gained familiarity with the rules and characters got into Paragon tier, combat often slowed to a crawl as everyone tried to wring every bit of advantage out of the system. (You can blame me and my players for this if you like, but to my way of thinking, a system is responsible for the incentives it offers, and 4E incentivized extreme rules focus during combat.)
Another thing that gave me trouble with 4E was bringing in new players. Introducing a newbie to the game is a great way to refresh your own view of it, and when I looked at 4E through their eyes, I saw a complex tactical game that was dominated by combat; not because my adventures were all that combat-heavy, but because the noncombat mechanics were fast and loose, so noncombat stuff got resolved quickly. An adventure which was 50% combat scenarios and 50% noncombat scenarios ended up being 80% combat in terms of table time. It usually took an hour or more to resolve a single battle, and if you hadn't mastered the rules or just didn't enjoy all those tactical minutiae, it was a really boring hour. Newbies quickly got lost in the blizzard of numbers and powers and conditions.
Finally, and most tellingly, 4E books functioned very well as rules references, but they were no fun to read. At first this seemed perfectly reasonable to me. After all, the goal of D&D is to play a game, right? If I wanted to read a book, I'd pick up a novel. But what I came to realize was that D&D didn't work like that. D&D demands a lot of creative effort from the DM, and that creativity needs fuel. TSR's rulebooks were more than just rules for a game. They were packed with inspiration and ideas. Just the process of looking up monster stats got my imagination working. 3E's decision to split up "fluff" and "crunch," and focus on the latter, made 3E books a lot less engaging. 4E took things even further. Sitting down to read a 4E book was like reading the dictionary.
More and more, I began looking back nostalgically to the TSR era. I even created a fantasy heartbreaker that tried to meld what I saw as the best of 4E with the best of the Red Box**. In the end, I mostly stopped running 4E. When the 5E playtest was announced, I jumped on it, and I'm now gearing up to run my first big campaign in a long while. 5E feels an awful lot like TSR-era D&D, except with coherent, clean, balanced rules, and I'm really excited by it. You might point out that I felt equally excited by 4E when it was released, and you'd be right; but that doesn't necessarily mean I'm just chasing the new shiny. 4E did improve on 3E in a lot of ways, and if I had to pick one of them to run, I'd still take 4E over 3E. But I'd take 5E over either of them, or over the Red Box, in a heartbeat.
[SIZE=-2]*I always played a wizard in my college days. When I told my college DM about the headaches my 3E casters were giving me, he said something to the effect of, "Now you know how I felt having you in my campaigns."[/SIZE][SIZE=-2]
**The resulting system actually bore some resemblances to 5E, particularly in the use of bounded accuracy and "big feats."[/SIZE]