I can totally relate to you, we too have a 23 year old daughter who we believe has "settled" and is similarly immature in dating and relationships, yet has chosen to align herself with someone we would never have her even be associated with. I get it. It's tough stuff! We are in a season of dealing with this real time.
Whatever your concerns are, it doesn't matter to others, but if it's a concern to you and your wife who know and love her best, then that's all that matters. In these situations, it's all about prayer, patience and great communication about your daughter's worth, her image as seen IN CHRIST and about each of you examining your hearts before the Lord asking for His wisdom, peace and His will to be done in your own heart as well as the heart of your daughter. I do feel strongly that it's very important that your daughter hears from your dad heart and your wife's heart on each of the concerns you brought up, pray about it and ask the Holy Spirit to give you just the right words to say and for your heart to be heard in it all.
Life is more than superficial looks, for sure, but how is his heart? Has he placed his hope, faith and trust in Jesus Christ as his personal savior? Does he put God first in his own personal life and then treat your daughter like the cherished treasure that he is, taking care of her and loving her as he loves himself? How's his heart? THAT is the true test of how worthy he might be to own your daughter's heart. If not, gently prod her heart and communicate to her what a loving date or what a loving husband looks like. If her boyfriend doesn't have those qualities then it's not right. Be led by peace. If you have no peace over this guy, but she does, after careful praying for the Lord's will, and has confirmation from other believers who know the both, then you have to trust that you have done your part and ask the Lord for peace in this situation. She is an adult and unfortunately will be making mistakes along the way, as did you and all of us. It's very hard to sit by and see the future for our kids and still stay the course of supporting them, and loving them, yet not agreeing with their choices. I feel your pain. Sorry we are all going through it. BUT.... God is good, He is faithful and is a gentleman who will not overstep our own personal will. Lots and lots of prayers and knowing that you did your part, now step out of the way and turn her fully over to the lover of her soul and watch Him do great and mighty things.