On Sunday, I went to a local hobby shop, and played in a 4e demo.
I was a halfling paladin. And I saw some mock ups of two of the core books. I have no details to give, just impressions.
1) I had fun. Chris, one of the guys in the gaming group I run, said he had fun, too.
2) The sets of powers they give characters are really dynamic. They've done a good job of keeping all the classes at about the same level of power, while still making them feel different. For instance, my halfling paladin had no fear of pain (and took negligable amounts of damage), though the warlock and wizard tried to keep as far away from opponents as possible. But when I was rolling bad, they were easily doing as much, or more damage than I was.
3) The real fun of playing is going to be choosing sets of powers that complement each other, and in using your actions and action points in order to get off bursts of powerful attacks. At low levels, this still goes quickly.
4) If you are a wizard, you have fewer powers, but no chance to pick dud ones. You have something to do every round. It works and it's fun. If you are any other class, you have a wider variety of things to do, but not so much that you hit option paralysis.
5) Don't include 5th level opponents in a battle with a 1st level group. It is a doable fight, but one of the PCs will invariably get soaked with damage and die. No fun at all.
6) Playing a halfling in combat is actually fun in 4e.
7) WOTC's sample adventures universally suck for plot. Much like the RPGA's living campaign adventures. I wonder if it's the same dudes writing them?
8) After looking at the sample monsters that Wizards has released, and some of the sample monsters people are kludging up on Gleemax, I've decided that I like how Wizards is handling monsters.
I like that they seem easy to design based on level appropriate damage and hit points.
I like that they are providing a range of creatures-within-a-creature: lizard men warriors and spellcasters. Gnome sneaks and spellcasters. Goblin harpoonists. Etc. Many of these options are just like the monsters with class levels from the later 3.5 monster manuals.
I know people rebelled against the classed monsters in the last few 3.5 monster books, but they make it easier for me in the long run. I think this philosophy of monster creation stabilizes the game by providing more choice in cleaner categories. It encourages working in those categories instead of creating a lot of goofy monsters that don't fit with other campaigns well. No flumphs. I think.
9) One of the things this monster design philosophy does, however, is bulk out the core monster book so that not very many creatures that people think of as core get covered
In turn, it presents you with a very small array of monsters for each level (6 or 8?).
Some of this will get fixed by the digital initiative, and people like me, who will make new monsters and post them.
There will be bitching from purists, but also, I think, from casual and beginning players who might not care about high level monsters and don't feel comfortable making their own, and people who don't plan to buy a lot of supplements.
I'm not sure how they could have solved this problem. I might have left out most of the high level monsters, since I would assume people would be starting with high level campaigns.
I personally would have liked to see some low level elementals. I don't understand why all 4 efreeti are 23rd level. C'est la vie.
10) Last, I see no evidence at all of a pet mechanics. I didn't see familiers, saw no summoning spells, and of course there is no pet class. I could be wrong about this. I looked at the PH much less thoroughly than the MM. Some people, my wife amongst them, will chafe at this. This will probably be featured in future releases. I'm hoping that somewhere in the three books there is some hint about what power level creature is appropriate for a PC to use as a pet or summoned beastie.
All in all, the good was really good and the bad is fixable with a little elbow grease. I'm thinking that it's a good edition of the game, and I will give it the core rules a good hard try out.