My 2 cents (probably not worth that much)....
I'm not sure why you let him go during the season at this point.
We really don't have anyone to take over--this has been discussed over and over. Besides placating the vocal fanbase, it doesn't accomplish much else.
The bigger issue is that no one will be recruiting--at all. You at least have Walters beating the streets to a certain degree, keeping Purdue's name out there from a recruiting standpoint. (although he is also keeping Purdue's name out there in other bad record-setting ways). I think the artlcle about giving him more time that was released a couple of weeks back may have been some handwaving to keep recruits talking with him. Think about it....the athletic department seeds a story giving him a more time. It may keep some recruits engaged. At the end of the season, they can let him go without walking back a 'we support coach 100%'-type statement. At least, I haven't heard the athletic department making these type of overt statements.
If he is let go mid-season, how much does that show the next potential coach that the potential for knee-jerk type decisions could be made going forward?
As unfortunate that the situation is, I'm not really seeing a reason why the athletic department 'has' to let him go before the end of the season.