I just got a 5250 to replace my 5200. Indeed they did fix the speaker problem. It no longer sounds tinny and the phone does not feel like it has a built-in subwoofer when you turn up the volume. Also it has a screensaver feature and supports downloadable ringers and graphics.
When you change a setting, it no longer goes back to the main screen. Instead, it goes back to the previous menu so you can make a few more changes before exiting out. Changing the volume also has some graphic effects now 🙂
I actually think this battery though is looser than my 5200.
BTW, this phone also supports 3G voice communications.