IMHO, the 4E version of healing is superior for the simple reason that even if you concede that 3E healing had more flavor (or "logic"), then it still remains that it is far easier to change the flavor of 4E healing than it is to change the mechanics of 3E healing. This is especially true for gamers that might not have much experience with house rules. I mean, how hard is this to do:
"All healing surges must have a power source, whether second wind, a combat power, or whatever. No more free use of healing surges during rests. Most healing stems from magic supplied from outside the body, but there is (still) only so much a person can take in a day."
Then introduce a few items or whatever to allow healing surges during rest, at a cost. You can even introduce a different kind of CLW wands, if you want (one that doesn't count as magic item use per day, since the surge is what is paid).

Me, if I wanted this, I'd probably use a ritual, with a low (but real) cost in time and components, with levels at 1st, 11th, and 21st (thus needing to upgrade at each tier). Then make it work on people in a small radius. Bam, done--you have a logical method for why magic is needed for healing. You might even have people toughing it out on that last surge or two, on the grounds that no one else needed healing.
On 4E multiclassing, I'm going out on a limb and predicting that multiclassing in 4E is what craft skills were in 3E: Good enough, consistent with the design, but not that drop dead, elegant powerhouse they could have been had they been better integrated with the core class mechanics. We'll never know for sure, but I think that the designers either neglected them too long, chickened out on certain approaches as too radical, or perhaps tried some things that didn't work. (Or maybe, all three.)
The obvious design, from the 30,000 feet perspective (i.e. not having to deal with the messy things, like details), is to extend the paragon path and epic destiny ideas down into the heroic tier. Something like, each class gets part of a second class for free, no feats required. You get roughly half the powers on the second class (and this is on the class chart). Let people trade off powers in their second class for more in their first class, if they so desire., since each pick from their original class is presumably not earthshattering. (If they are powergaming, they picked the earthshattering powers with the main class picks
.) Now, if someone wants to use main class picks to get even more second class powers, charge them feats. Do the same for someone wanting to dabble in a third class. In effect, the whole thing would be kind of like a low-grade, 3.5 gestalt, which is what the paragon path and epic destiny are.
My guess is that the reason this wasn't done is because it increased the number of encounter and daily powers to the point where the game would (theoretically or from playtesting) bog down. Since our group wasn't having any problem with 3E/AE gestalt, I think it would work pretty well for us.