This is actually a very good idea in general. If the programmer left because of some sort of perceived problem, and the company doesn't see the perceived proble

This is actually a very good idea in general. If the programmer left because of some sort of perceived problem, and the company doesn't see the perceived problem as actually being an issue, then they're unlikely to change their mind when you join. If the programmer left over something that's also going to upset you, and the company doesn't agree that they need change, then it's a bad idea to join. Alternatively, if the company also perceived the problem as an issue that needed solving, but were -- for whatever reason -- incapable of doing so, then they might be worth a shot. Just don't join and then expect them to change the way they do business in order to suit your needs.