Solution 1) long press on a trouble word once you edit it, and add it to the dictionary then the phone learns to guess better and soon enough your phone will be 90-99% accurate, everyone is different and this is a "design feature" so your phone customizes its learning of your common phrases and quips.. I agree simple words should be there but who cares its fixable.. If on the other hand swype is simply not recognizing the "d" key I would suggest getting the latest copy of swype from the store and re-installing to see if it fixes issues, if not return your phone and get one that works, mine is fine.
Solution2 the phone screen was not turning off is because it was plugged in to car charger and you have a setting to keep the screen on while charging... or your phone is broke and needs to be returned.. again not commonplace S3 is bad-ass phone! Just takes time to remove network carrier crap, return to factory then setup and optimize, its the difference between buying a pre made pc with bloatware or a custom one. Don't knock its customization perks, or Samsung will start making barely customizable zombie phones, with testicle wrenching cloud updates like Apple do.
The bigger picture..
Understand phones don't have to be like bodyparts (constantly requiring nourishment or repair) but the fact is phone company's want you to tend to your phones needs night and day, its a proven way to sociologically make you need your device more and use it for everything, its the best way to monitor a populations choices and ultimately the best source of free market research and census the government/google/apple/all network carriers has ever developed.
If i were to complain about my phone. i would complain that still to this day there is no phone with a decent battery life (yes we have the technology to develop cheaper human lifetime lasting battery's that hold a charge for a week, don't think we don't. it's just not a corporate level interest to sell efficient products when you can sell 10 over 1) or even more annying regardless of how amazing the hardware is dealing with an android operating system for phones that requires some serious editing to remove statistical collection and carrier ID / bloatware... before the phone is even ready to be "used".
This world is pretty sick when you actually get down to the nitty gritty of it!