You may be right John - from the blower design I'd assumed there were vents on the bottom, but there don't appear to be, at least from the unboxing videos I've seen. Having the intake and exhaust right next to each other is traditionally a no-no for cooling, off the top of my head I can't think of any other piece of consumer electronics that does it like this.
I find it interesting that it looks like AMD is going back to a (sort of) shim for both the PS4 and Xbox APUs rather than the heat spreader used on current desktop chips. Was this something specified by MS/Sony I wonder, or something AMD decided? Does it result in better heat transfer?
Uh, BOTH systems use torx security screws, it's stated quite clearly in the Xbox teardown. Also, you can get security screwdrivers at pound shops here in the UK so it's hardly an issue for someone who has spent £349 on the console itself!
The replaceable hard drive (without invalidating your warranty) is a BIG plus for the PS4, so if anything the PS4 should score higher.
Look at step 21, the other memory chips are on the board's underside.
Uh, you might want to take another look at the teardown pictures. Step 23 very clearly shows the underside of the heatsink plate, along with the thermal paste. As with the Xbox One (and other AMD APUs), the GPU is on the chip, so is cooled by the same cooler. As for your concern over only 2 screws being used to secure the cooler, that's really not going to be an issue for a heatpipe-based cooler like this. Massive, heavy copper heaksinks (like some Zalman ones) are secured with similar 2 screw brackets in PCs without any problems.
For me, the real concerns are that the fan draws air in from underneath the console - I wonder how many of these will end up being used while on carpets, and how much dust will end up getting sucked up. Also, that radiator looks awfully small when compared to the one the Xbox has; that either means more airflow is needed (so potentially noisier) or coping with higher temperatures.
Traditionally, blower fans blow air out of a system (hence the name). So no, it isn't drawing air in through the PSU, that wouldn't make much sense.
Also, I've seen plenty of 10+ year old systems with BIOS batteries that are still fine, so I've no idea where you've got that 4 year life from.