Welcome to the forum.
I believe what you are asking for is
1: How to keep TF3D in landscape
There is no official TF3D in landscape. You can flash a ROM that has it built into it, or edit TF3D to your liking.
2: Fix the lagging keyboard
There is no consistent fix for this that I know of, I have tried reg edits, cabs etc.
3: New theme like the iPhone or G1
4: New lock mechanism?
See
Throttle Lock
Is that correct?