Well, I'm already organizing a playtest of 5 classes out of the bunch, but for the moment I have to say this might be the biggest misstep in Paizo's path so far. And I quite love Paizo and their products, to the point that I'm probably partial even to bad decision-making, so this speaks volumes.
The first problem is the concept itself. It's true, many people here have reacted negatively within minutes, but isn't that weird on its own? There's something utterly uninspiring in the concept of these mixed classes. Some people might love them, of course, and other people simply won't use them... But a blunder is a blunder, and the signs are there.
When I proposed the playtest the general reaction, after reading the playtest document, was kinda "meh".
It has never been like that with previous playtests. I don't trust gut feelings, that's why we're doing the playtest after all, but there are things that don't look bad even on paper.
Take the Swashbuckler, for example. His Panache pool is equal to his Charisma modifier. His 1st level Deeds, Opportune Parry and Riposte, need 1 point each to be executed and 2 uses of Attacks of Opportunity.
This requires a Charisma of 14 and a Dexterity of no less than 12 (but any Swashbuckler will want a lot more than that). And at 1st level it needs Strength to hit and do damage, because Swashbuckler Finesse is at 2nd level, but doing so would gimp him even more so I'll suppose high Dex and low Str.
All of this for a nifty trick that probably won't work ("Wanna best my attack roll? Go ahead, make my day" said the Fighter) and that recharges on critical hits or enemy deaths. Which is to say: not often until higher levels, not in a reliable way.
On a Standard Point Buy that's simply not a viable option.
On a High Fantasy, it's a very low-powered alternative to Fighters.
But I digress. The point is not that these classes are low-powered when compared to Core classes: I understand that power creep is a legitimate concern and I wouldn't want classes that skyrocket either. The point is that the mechanics simply don't seem to work as intended, and that's because mixing classes is really tricky. Maybe even trickier than designing completely new ones (a feat, pun not intended, that so far has given us really interesting and fun stuff to play with).
I'll leave it as it stands for now and I'll comment after we've done the proper playtest, but for now I don't see this going anywhere and I understand the negativity floating around.