A bit more info on this after playing around with it some more, particularly relating to the bold.
It seems that when the defensive suggestions are first made to you, they aren't taking the opponent's formation and personnel into account, which can lead to unbalanced stuff like base D against 4 WR. But...if you cancel out of the suggestions and go back in, it will update the suggestions to reflect the personnel the opponent will have out there, which means it will match base D to 2 WR, Nickel to 3, and so on. It's two quick button presses as the play screen comes up and you'll still have plenty of time to choose a suggested play (particularly with the other thing I'm about to mention).
It's a time-consuming pain scrolling through all the frequent and community play suggestions just to find the strategy ones, but you can filter to where only the strategy plays will show up. All you have to do is press right on the D-pad on the suggestions screen and you'll get a list of only the strategy plays. You'll get 3 at a time and can scroll through them with up and down.
Hope that helps! I didn't know about either of these until I started really messing around with the suggestions.