You cant JUST switch to Wordpress. Blogger has a URL structure of its own which is less malleable than Wordpress. Wordpress may be able to mimick it bu t you'd be locking yourself into the blogger pre-defined URL Structure...just keep that in mind.
Preserving URL titles is an absolute must, unless you plan to 301.
The problem with 301 is if you start going 301 crazy you will notice performance issues whether you do it in .htaccess or databse.