I found a lot of these problems were resolved by doing a system cache wipe ; it went from hardly charging at all to charging in sensible time. Currently the tablet has been sat lurking in an IRC channel on my nightstand, off charger, for at least a week, and still has more than 40% charge.
The only cable problem I had was when I dropped the thing on the floor when charging ; I had to rebend the shroud on the USB socket back into place. It's still a bit loose, depending on the cable you use.
Yes, you shouldn't have to tinker with things. I can't say I'm impressed with the overall quality of Asus's tablet offerings - my girlfriend has one of their transformer tablets, and the keyboard dock has failed - the connection seems to work fine, because the touchpad part still works... just the keyboard doesn't.