I had that same problem on mine. I'm running a ROM that I put together myself tho and what seems to have fixed the google navigation problem is just deleting it from your system apps and then downloading the updated version and putting it back into your system apps and giving it the right permissions. I think the force closes are caused by id mismatches but I'm not completely sure.
I still have some Force Close issues using Navigation most times. It will FC, then still be in my status bar and open. Then close again. Seems pretty consistent. I tried doing what you said above, but Maps wouldn't open anymore and I reflashed the ROM, so I'm back to square one. So after you delete it, download new one from market, or from where? Kinda confused. Yet I get the idea I still don't fully understand, explain a bit better? Sorry. LOL.
Other then that, this is a great ROM and have the ICS theme and everything seems very good. Just navigation acts up a bit.
EDIT: I have noticed now the Speed Test app tests the entire length of the test now. I assume thats the ICS theme with the throttle removed? Either way I still only get about 90-120 kbps. Better, more consistent but still slowww! lol
