Go check iMessages in Settings > iMessages on all of your iOS devices, one of them is probably signed out. I went through this last night. I was missing messages and I saw that I didn't have my cell phone number on my iPads. So I went to my iPhone, saw that I wasn't signed in, sign in and then it started showing up everywhere.
Pretty much every product launch is a beta launch, there's never been a prefect software/hardware release. Apple sometimes get it right, sometime they don't and it takes time to fix it.
I'm sure Apple is fully aware of the low memory problem and will optimize iOS 7.1 release for iPad Air/mini soon to tackle it properly.
Why are you disappointed? Your logic makes absolutely no sense. You should be happy that they're fixing and improving bugs as quickly as they can. Apple doesn't have to do this and they could've just leave it alone until iOS 8 comes out.
There's never going to be a hardware without any software updates required to make it perform better.
Even PS4/XBOX are being releasing with mandated software update required on the FIRST DAY. Heck, even Telsa cars are getting software updates over time and they cost over 70K.
Hardware is usually finished first but the software is going to take time to get it right, it's never going to be perfect on day one.
Note, that doesn't excuse anybody for being sloppy but it's just the nature of software development and no, no amount of money and QA processes would ever prevent this.