SMS Texting And T9 Input...

Texting is done with the full qwerty keyboard in the iPhone, not the phone dial pad. There's no need for T9 (which isn't supported).

will there ever be an app designed that will display the keypad and that can be used for texting

We are just users such as yourself and have no knowledge of Apple's future plans for new features, let alone 3rd party designed apps. My guess is that 3rd party apps can't do this because it appears to require access to certain core function API's that Apple doesn't allow.

It's doubtful that you'll see it on the iPhone. T9 was designed for phones that lack a keyboard.

Switch to decaf and it won't seem so slow.

SMS messages are contained in the backup, as distinct from syncing apps and media to the iTunes library.

http://support.apple.com/kb/HT1766

PLEASE, do not type everything in capital letters. It is annoying and hard to read and wastes time in typing that way.

Text messages are synced with your backup on your computer, there is software to extract them from the backup should you need them and there are apps to manually save them to your computer.
http://www.ecamm.com/mac/phoneview/

I'm totally with you! I find the keypad much clumsier to use than my primitive flip phone's T9 number pad. In fact it might be a deal killer for me. I used to be able to text without looking but now I can't even text while walking.

There are some paid apps that are supposed to do T9 entry. Search for "predictive text" in the app store. I haven't tried any yet, so I can't recommend one.