The whole point of saying that the Big Bang is an explosion is to generate the redshifts with pressure gradients, right? And those pressure gradients would be encoded into the CMB right up until recombination, right? So you'd see the signal of the pressure gradient in the CMB. The point is, you can't get redshifts from a pressure gradient without seeing the pressure gradient in the CMB, unless you are really at the center of the "explosion" (which does have to have a center to be an explosion).Yes, and the breakdown between them is merely a reflection of your own chosen coordinatization, it isn't "physical".

Here's how an explosion works. You have a pressure difference, which is a difference in kinetic energy flux. That means you have a volume that has a net kinetic energy fluxing into it, and this shows up as motion of that volume. The total amount of bulk kinetic energy that appears in the volume is entirely given to you by that pressure difference, so you simply can't have one without the other. During the time when the CMB was coupled to the gas, radiation pressure played a key role, so a large fraction of the energy in the universe was still in the form of pressure, not bulk motion. Since the CMB clearly encodes what was happening during that epoch, you would clearly see the pressure gradient responsible for the expansion. Later on, the pressure is a very weak player and mostly all you have is what you might call bulk kinetic energy, so by then the pressure gradient would no longer be very apparent, but that's not the case during the radiation dominated epoch. The formation of the CMB happens after about a 40-fold drop in pressure, but that implies the pressure difference across the visible universe would still be on the scale of a few percent-- easily detectable by WMAP by orders of magnitude.
No chance, such a model only accelerates at the edges, not in the center part you're claiming we are seeing. As I said, you can't get the bulk motion without the local pressure gradient, the two are one and the same-- if you want that center part to expand too, the pressure gradient has to eat its way into that region, again becoming clearly visible.
You are asking the right question, but coming up with the wrong answer.

Being close to the center might reduce how well we could see the pressure gradient, but we have so many orders of magnitude to play with that we'd have to be really really close not to see the gradient with WMAP. Even if we were at the center, I would imagine that more careful physical investigations could rule out the explosion idea, but you'd have to look at very careful fits to the expansion and the CMB formation. I would certainly imagine that has been done, but if not, it should be.

Actually, I'd say just start the whole thing after inflation. My argument shows that what happens next was not an explosion, even though there was plenty of pressure around to cause further expansion if that was indeed its cause. What was lacking was pressure gradient, and that's what you actually need to be able to explain motion as being induced by an explosion. Then you just say that inflation couldn't have been an explosion either, because of the relativistic physics needed.

As for before inflation, I'd say that all bets are off-- we really have no idea what was going on before then, even if we assume inflation did happen. So you can imagine you had an explosion before that, but what's the point? You still have 3 phases of Big Bang, and the only one you can imagine as an explosion is the one with zero observational constraints. You still need explanations for the other two, and it's really only the last one that you actually observe. The sole explanation for that one comes from general relativity, not explosion physics, this is my point. That's why "Big Bang" is an unfortunate misnomer.

No, it would violate special relativity, because to use special relativity you have to have a global inertial reference frame, and in such a frame, most of the universe is separating from you faster than the speed of light (given our interpretation of current observational data). That's the violation that requires general relativity to resolve, because in general relativity, the universe does not possess a global inertial reference frame, so it isn't a problem. You are now talking about the Milne universe, but that doesn't fit WMAP and supernova data.

I hope I've clarified that now.
It's responsive. Reason 1 was the absence of CMB gradients, and the "other reason" is that no special relativity model, explosion or otherwise, could fit the WMAP and supernova data. You need general relativity, and it isn't an explosion. The explosion stuff is just a picture to satisfy people with very little physics education, but personally I don't like using wrong models to give people a false sense of understanding. It's not that hard to say it basically right, and still make it understandable to people with little physics background.