Well I would love to be in their closed play test, and show them the math that goes with everything, but apparently they can't stand a dissenting opinion for whatever reason.
Even if they were to get everything balanced right, they still missed one thing:
I want to play a game that has interesting equal choices on level up and during each round of each encounter. Something that only a few classes in 5E get. I don't mind if there is a simple sub-class for those that want it, but I want a class with lots of options and tactical choices.
I appreciate you sending me the public play test files though. Now I can do my math on them, but really there doesn't seem to be much difference in the most effective spells between the 2 packets. The biggest difference seems to be the spell casting DC and the increased proficiency bonus. So on the one side saves are easier to make, and on the other attack roll spells will hit more often.
Thankfully the rumor is that they brought on the Magic guys for math tuning - so I pretty confident that the math will get finely tuned near the end of the process (this is just what I've heard living around Seattle). I also do know that in many cases, the options sent out in the playtest packet were to reaffirm the idea of removing something - that is, they didn't think something was a good idea, but they sent it out to make sure other people saw it was as crazy as they did. While I can't comment on specifics, unfortunately for WotC, I know at least 2 playtesters they have that are Ph.D mathematicians, and at least 10 more who have advanced math & engineering degrees.

They most certainly hear about poor math decisions.
I can't quite put my finger on whether all classes will get meaningful choices at every level. But, I'm not exactly sure if that's what is best for an introductory RPG.
So, I think part of the disconnect is that while there is a lot of talk at whether the game is aimed at 1/2E players, or 3E players, or 4E players..I don't think it's necessarily aimed at any of them. One of the things I've heard bandied around at various RPG companies is this idea that there is a dearth of brand new younger players. IE, 1E could be played at lunch time in an hour. That's how a lot of people learned to play it as kids. One of the problems with PF & 4E to some extent (IMO) is that they were systems that were aimed at people who already played RPGs. IE, while you will have the market grow a little from folks bringing their kids into the system, Pathfinder / 3E and 4E are really complicated systems to folks who don't know what a d20 is. Even the beginner box, which is a fantastic product, has a distinct jump between the box and the core game.
I have a group of younger players who are 2nd generation D&D fans. Their parents tried to teach them 2E / 3E, and it went terribly, and they ended up joining a 4E Encounters game. When we switched over to the playtest for NEXT several months ago, one of the things that has stood out to me is that the ease of which they can pick up NEXT, and how much fun they have. Everything makes "sense" to them, in both a mechanical and verisimilitude way, and the ease of which off-the-wall actions can be adjucated makes the game far more engaging for them. Operation "Each of us grab one arm of the vampire, one of us kick it in the balls, one of us poke its eyes out, and the last of us cut off its hand and take its axe" is a full go in 5E (and was doable in 4E, albeit a little harder) and is easy to do. On a quick aside; younger players are suuuuuuuuuuuuuper sociopathic in hilarious ways. They genuinely don't know "better", so they come up with the craziest stuff and most sadistic ways to deal with bad guys. Also, Lord of the Rings is their nerd cred argument at D&D.
"I've seen all of the LotR movies"
"I've seen all the extended editions"
"I've read the books!" and etc...it's really sort of hilariously awesome.
I think NEXT is really aimed at being a big tentpole game. If PF and 13th Age and 4E are really good at taking a certain percentage of the pie, I think NEXT might be the edition that tries to grow the pie itself. I think it does a really good job of it. It's not going to be as process simulation as 3E, and it's not going to be as good of a balanced tactical war-game as 4E. (Insert whatever you believe defines each edition, that is my intended point) But, IMO, it does like 80-90% of both at the same time, and to me, as someone who grew up on 3E and actively GMs Pathfinder, but find 4E my favorite (published) edition of D&D by a landslide, that's a really good game for me. I love the fact that my younger players all want me to come DM for them on their birthdays, and that they want to do 5-way 10th level Lord of the Flies (you can make alliances, but only one winner, and you can't share credit on kills, person who knocks you below 0 gets the credit) you die and respawn the next turn at full everything PvP (this is why I am fairly certain mages as they currently stand are not too scary at higher level) some birthdays and they want to fight a dracolich, a dragon, and a lich at the same time on other birthdays. That's a game that can stand up next to video games and other forms of entertainment. I think we need that.