I previously worked under "Mr Jones", who was a terrible team leader/manager - no shielding from stakeholders, no support with issues, promised the world to stakeholders and the team but never delivered and the entire team ended up leaving.
Enter my new job, where my new manager is resigning and they are interviewing replacements.
Mr Jones just had his interview here for that role and word is they're keen on him.
Would it be unethical for me to voice my opinion of him to the hiring director?
I know part of my disapproval is on a personal basis (promising me a comparable salary to my colleagues for 18 months but never actually signing it off is big grudge) but I'm genuinely concerned after seeing how people work in this business that he'd cause a lot of stuff to collapse (projects and teams included) as I've seen in the last company. Also, it might be reactionary and childish, but I'd immediately resign if he was my manager again.