The latest DnD Next playtest packet is out. I missed it for awhile due to my travels but I have had some time today to peruse it and there are some really good changes. The main thing that changed is that the balance of classes and spells was massively improved. In the previous versions fighters were amazing combat beasts because they output unbelievable damage while all other martial types sat in a corner and cried. This is very much corrected and it seems like the big difference between the classes is that fighters are the toughest. They have the option to use heavy armour (they probably shouldn't, because Dexterity builds with light armour are better) and shields but more importantly they have more HP than everybody else and can parry to reduce incoming damage. That seems like a reasonable balance; rogues and monks get lots of cool tricks and sneaky things and fighters are hard to kill.
I have to say that I like the changes to spells, though those changes are trickier to math out from a quick read. There is a new mechanic where Save Or Die (SoD) spells aren't cast if the opponent saves. For example, if you try to turn somebody to stone you can keep on casting the spell until they fail their save and are affected. However, you have to maintain concentration on the spell for a full minute to actually kill them so it is entirely possible for an opponent to turn a party member to stone, creating all kinds of tension and drama, but for the person so targetted to survive because their friends beat up the baddie just in time. It doesn't address the PCs using SoD spells to destroy bad guys on round 1 but you can't have everything.
One thing that the new version adds in doesn't work so well and that is the Skill Die. This is a replacement for bonuses on skill checks and it is essentially a die that starts off as a d4 and eventually gets to a d12 which you add to any skill roll where you are proficient and some classes can add it to other things. I don't see any need to roll additional dice when performing skill checks and I would prefer it as a static number, particularly in the case of rogues who roll it twice and take the best result. Too much rolling for no benefit, I think. It also has some other weird attributes because fighters get to roll it to reduce damage taken and rogues can spent it to use their extraordinary powers but bolting all that onto a system designed to let people get better at skills seems bizarre. I think they stretched the Skill Die to do too many things and it doesn't do any of those things well as a result.
Though there are many improvements to the system there are still some significant problems, particularly the incredible lethality of the system. Low level characters all kill each other in single hits and high level characters take a long time to die; although this is good from a nostalgia point of view I don't much like it from a numbers perspective. I get that they are trying to be just like 3rd edition and give people 1d6 hit points per level but I think that is one of the systems that seriously needs to get the boot.