1. If you're going to do something that might get you fired, get another job lined up before you do it.
2. The leverage "threaten to resign" only works once; if you don't follow through it won't be credible again; and it marks you as having one foot out the door, making it less appealing to invest in training you or give you new responsibilities.
3. Even if you use leverage other than threatening to resign, moving jobs is guaranteed to get you away from your toxic boss, whereas trying to fix things isn't guaranteed to work. And at the same time you can probably learn some new technologies and get a salary bump. Once you've got another job lined up, you might as well take it.
4. Telling everyone what you really think in leaving e-mails / exit interviews never changes anything in the company, but might make you enemies or get you a bad reference. Why bother? Instead give them some bullshit about how it's a great company and you just felt it was time for a change.
Of course, if you can confront the situation in a way that doesn't risk getting you fired, the above logic doesn't apply.
Don't threaten to resign. Make your argument, back it up with data and evidence, let managers the space to do the job they are supposed to do. If then they don't fix the problem, then just leave.
There is only downside for threatening to leave, it scuppers your future in the company. As michaelt notes, don't bluff, have the next step lined up. At that point, there's no value in threatening to leave. Just hand in your notice, if they realise your value they tend to counter-offer anyway. But be sure leaving is the right thing for you.
1. If you're going to do something that might get you fired, get another job lined up before you do it.
2. The leverage "threaten to resign" only works once; if you don't follow through it won't be credible again; and it marks you as having one foot out the door, making it less appealing to invest in training you or give you new responsibilities.
3. Even if you use leverage other than threatening to resign, moving jobs is guaranteed to get you away from your toxic boss, whereas trying to fix things isn't guaranteed to work. And at the same time you can probably learn some new technologies and get a salary bump. Once you've got another job lined up, you might as well take it.
4. Telling everyone what you really think in leaving e-mails / exit interviews never changes anything in the company, but might make you enemies or get you a bad reference. Why bother? Instead give them some bullshit about how it's a great company and you just felt it was time for a change.
Of course, if you can confront the situation in a way that doesn't risk getting you fired, the above logic doesn't apply.