My family did skip 1900 this year and added The Boathouse. However, we did CRT and Akershus so my girls didn't miss 1900 that much. Both girls (8 &4) really liked The Boathouse. It was cool to see all the boats. The food from the kid's meal was delicious, as well as the meals for the big people. The atmosphere and the service were excellent. The Boathouse is a great place to go if you're visiting DTD/Disney Spring. It is really not expensive as long as you don't order the steaks. The average entree is less than $30 for adults (cheaper if you order burger/sandwiches), $10 for kids. If you don't have other character meal ADR and your girls love to meet princesses, I would suggest to keep 1900 and have lunch at The Boathouse. For me, a Disney vacation is more for my girls than myself. Although, personally I would choose the Boathouse or Raglan Road in a heartbeat, I still would pick 1900 if that's what make my girls happy.
No matter what you decision is, you can't go wrong with either. Both great for the family.