I'm not usually one to kiss and tell about a previous employer.
One of the main problems that I have with Air Wisconsin is that their offer letter is not a true offer letter. An offer letter from Air Wisconsin means that you made it to phase 2 of the interview.
The problem with a small regional airline that burns through so many people in its training is that they are federally required to fire/fail a certain percentage of all those pilots that they hire per year. Not everyone can just resign and walk away somewhat clean.
So, every pilot should know that when they sign Air Wisconsin's offer letter that they are taking a big risk in making it to a major.
If you have an upcoming class date for Air Wisconsin you should know that it is not too late to still drop out without them firing you or failing a checkride. I recommend immediately applying to 4-5 additional regional airlines. What is the harm in at least delaying your class date for 1-2 months and seeing if you can get another Part 121 opportunity? Accept an offer letter that means something.
Again, if you enjoy training events and are a good test taker than disregard.