The volatility of and turnover in tech support is offputting to some people. Since general support partially functions as backfill for almost every other area of the Operations department, there are periods of brain drain as people move into the other positions mentioned in the Pros,
The training for support techs is lacking, but that is really due to the nature of the products. They are so large that each new hire could spend six months in training and still not be able to answer client questions the first week on the phone. They're products that need to be learned by doing.
There have been a number of departmental restructures in the past four years, in the name of optimization. Sometimes, it takes a while to figure out who runs what.
Because of the investment the company has in each employee, sometimes management is a little slow to cut out the dead weight. They spend time creating action plans and coaching but it doesn't always work.
Sales...well, it's a sales department. They don't have any idea what the product does but they'll tell the clients it can do whatever they want. That isn't anything out of the ordinary if you've ever worked as a vendor before. Sales will do whatever they have to do to get a signature on the contract.