Here is why I'm worried and giving up hope the longer and longer things drag on...
Microsoft, IMO, has nothing to show off that isn't already available on other platforms or that aren't really that exciting, and the basic things they need (seperate volume controls, VPN settings, WiFi sleep settings, the BASIC THINGS A MICROSOFT PRODUCT SHOULD HAVE) will be missing (from the leaks so far). NFC...? That's cool, but Android has it. Kid's Corner....? Ok...? Xbox Music and stuff....? Ok...? It's like everything they throw out there that is supposed to be exciting is more like "meh...". When they reveal Windows Phone 8 on the 29th it will be exactly like the iOS 6 event: dry and boring (with the exception that it will be on a worse level because...well....it's Microsoft and not APPLE...the company ppl think can do no wrong...). Everything they show off will have already been known through leaks and there will be nothing to show off that will get ppl to say "Oh ok...that's what they made us wait for". The whole "secrecy" thing is ridiculous, and if truly because the OS was SO incomplete to the point that it couldn't be fully shown off on video for 2 WHOPPING WHOLE MONTHS before their event then that's a bad sign. Couple that with the fact that developers can't take advantage of the new hardware capabilities with the new SDK because of "secrecy", and you'll have a new OS with old 7.5 apps that won't compel anyone to change or upgrade....
The other reason is because of the hardware. Yes, it is a well known fact (even amongst bloggers and reviewers that HATE windows phone) that the OS runs perfectly on single core chips, let alone dual core. What worries me is that we are following the same cycle of getting recycled SoC's like Windows Phone 7. The Adreno 225 in the S4 is weak compared to other SoC's. No, this doesn't matter for the OS, but it does matter for games and higher end apps that Microsoft preached would be coming "with ease of portability thanks to Native Code". However, this is remedied by the kernel change, making it possible for scalable hardware (64 cores or w/e they touted).
Anyway, I'm just loosing faith in Microsoft's ability to deliver and really know how to do it. I welcome the much needed changes in Apollo and new kernel change, and I will get a Windows Phone 8 device out of contract when the prices drop (Lumia 900 will be fine until then), but I can't lie when I say that I have been eyeing other platforms (all of which I have used before). I've owned a Galaxy Nexus and a 4s while still using my (now old) Lumia 710, and Windows Phone killed them in speed, efficiency, and beauty.
We'll have to see...but I'm slowly loosing faith in this OS...