I spent a good hour deleting 6 months worth of weekly transactions that weren't in the right place ( MYOB was in a merciful mood and actually let me delete them!), and each one had to be painstakingl...
I do agree with 2 points - normally audit trails should be used to deal with newer treatments, policy changes etc. BUT, if the data just shouldn't bet there - ie migration data is wrong or it is simply easier to re-import then bulk delete has its place. Efficiency is key noting important functions such as security and audit control.
See my next post regarding bulk reclassification of transactions.