If you ever give feedback on a situation or wish to criticize someone, let me urge you in the strongest way possible to give it voice to voice. That means if not face to face then at least by phone or SKYPE.
When speaking with someone you have the ability to work through the comments or criticisms with ongoing dialogue. You can explain what you need to explain. You can each recognize nuance and subtlety. You have a much better chance of coming to a positive conclusion.
But… when you write it, for example, in an email, that ongoing dialogue is impossible. The reader can’t read that nuance or your honest desire to help. And that leads to all sorts of misconceptions and possible negative fallout. They might get their hackles up and blow it all out of proportion, when that was NEVER your intent.
We were recently involved in a situation started innocently enough by a person trying to make a minor alteration to a system. But the party it was directed to misread the intent and took major offense. The fact that the person sending the email copied just about everyone even remotely associated with the situation didn’t help matters either, but that is another story for another day.
Not all of us are writers who can express perfectly what we want to articulate and have it completely understood. I know I sure can’t.
Your best bet is voice to voice.