One of the things I have seen in many email builders is an automatic spam scoring. As you write out the email (or template), it gives you a score for how likely that is to trigger a spam filter and gives ideas of what you can do to reduce the likelihood of being put in the spam box.

This is huge for all of us since any spam warnings that our sub-accounts get also affect the entire account. It could help increase overall deliverability and help all users across the platform.