We like any of the MK resorts more than the Epcot resorts, especially for romance. Looking at the castle from your balcony is magical! Watching wishes fireworks is wonderful from your balcony as well. You can watch some of the high Illuminations fireworks from some of the Epcot resorts but you can't book that view like you can book an MK view in the CR, Poly or the GF. Plus, without the castle, it isn't the same, IMO.
If the MK calls to you, then a MK resort will be amazing. The rooms are larger than at the Epcot resorts also. Which resort is a personal choice. We love them all in different ways. The TPV from the CR tower is the best, IMO, but the TPV from the Poly or the GF is nice too. If your dream is the CR, I would go with that. The CR is awesome with the monorail going right through the resort, the best views, comfortable rooms and easy transportation everywhere - including the other resorts!
For romance, you just can't beat the Poly or the GF. It just depends upon which style suits your definition of romance - tropical island or Victorian England. We chose a split stay between the GF RPC King room and BWI deluxe room CL. It was very lovely, but the BWI room could be a little noisy in the evening.
If you are more inclined to spend your time in Epcot or DHS, then an Epcot resort can also be good. Or if you like more night life, bars and strolling around world showcase at night, then Epcot area resorts may be more your thing. BWI has a great CL if you are considering CL. If not, we have found even the standard rooms are very nice here.
We found that we loved the MK area when our kids were in school, then we preferred the Epcot area when they were teens and early adults, now we are retired and are back to finding the MK resorts just feel more like Disney to us. It partly depends upon your age, your preferred interests and your personal preferences. Whichever you choose, all the deluxe resorts offer something special and unique to them.
Enjoy!