Do you think managers should be ex-software developers with a lot of experience (10 years...)?
(How can a manager with no software development know the difficulties that come with programming large scale projects?)
I'm not trying to put managers in a negative light, but I am interested to hear from other managers and developers that do find ways to work together productively...
Not necessarily, but it certainly helps for them to have somewhat technical expertice/experience - otherwise it's far too easy to misunderstand each other.
No.
Being good developer doesn't make you a good manager, and being good manager doesn't make you a good developer. It's two different jobs.
Not necessarily. It certainly makes for a better manager if he/she understands development, but on the other hand being a good developer does not automatically give anyone good management skills. The most important thing to recognize is that development skills and management skills are not the same.
A manger doesn't need to be a good programmer but IMO they need to have enough programming experience to know when someone is lying to them. It is always going to take a developer less time to explain there idea to someone that some technical insight. That said, being a good programmer also doesn't mean someone is going to be a good programming manager. Managing programmers requires completely different skill set.
If people are interested in learning how to manage and have a programming background they will have to work at it, the same way they worked at becoming a better programmer. Books like The Mythical Man Month and Managing Humans are a good place to start IMO.
I'd put it like this: a programmer needs to acquire some knowledge about the domain he's working in to do his job well, yet he should not presume that his limited and possibly outdated experience means he doesn't have to listen to the domain experts.
The same is true for development managers and programming. The main difference is that due to their higher position in the corporate hierarchy, (bad) managers are probably more susceptible to believe they know better than the full-time experts.