In some cases, I might agree with you.
Not in this one.
There are NINTY seperate applications this thing must talk to. On the Registration page ALONE, there are ELEVEN CSS sheets (not one -- ELEVEN) and 57 javascript *libraries* -- not the standard JQuery ones, I mean custom-writes -- much less actual call-outs.
Start fresh and you have a small shot. Keep THAT code and yer dead.
(I hope they keep the code) lol
I could start with MySql, Apache Wicket with Twitter Bootstrap and crank out that site in two weeks, bug free.