If you have lot of column then it will take some time but it will not hang. Sluggishness issue has already been fixed in our 5.13 development tree. You can check out the 5.13 BETA from: http://www.webyog.com/forums/index.php?sho…view=getnewpost
You were right, it's not hanging, just very slow, anything up three minutes for an update.
I've been doing some research and as you say it is worse on tables with more columns, but it is all tables on both a local Windows XP MySQL server and on a Linux server.