You make good points, but I think they might be mostly applicable to someone whom you expect to be productive day 1, as in a contractor or on a project with an extremely tight deadline.
I have been in the microsoft ecosystem for many years, and then I did an internship at a Java shop. Granted, a lot of the things there were new to me, but most of them were parallels from the asp.net world. Even if you are looking for a senior dev, maybe start them out as intermediate for 3-6 months, and then re-evaluate them to see if they've caught up and deserve to be made senior at your shop?
> Even if you are looking for a senior dev, maybe start them out as intermediate for 3-6 months, and then re-evaluate them to see if they've caught up and deserve to be made senior at your shop?
That's hard to do in practice. Do you pay them as if they're an intermediate or a senior dev? If they're really a senior dev who just doesn't know your stack, then you're going to have to pay them senior money. What happens if they don't pick it up as quickly as you hoped, and you have an intermediate dev pulling down a senior dev salary leaving no budget to hire a real senior? That's an awful position to be in - development groups without strong technical leadership have high turnover and low velocity. It's almost always better to hire the right person up front.
Ideally you can promote from within for those types of positions, but not every company has a deep bench of talented people.
I have been in the microsoft ecosystem for many years, and then I did an internship at a Java shop. Granted, a lot of the things there were new to me, but most of them were parallels from the asp.net world. Even if you are looking for a senior dev, maybe start them out as intermediate for 3-6 months, and then re-evaluate them to see if they've caught up and deserve to be made senior at your shop?