IMO, i would say banff might not be a great location for a romantic honeymoon...the banff springs hotel, while stunning is extremely pricey and the rooms are "old style" AKA small. The hot springs are so developed, it is actually a chlorinated pool heated with the springs water. Plus banff is quite busy and full of city folk from Calgary.
KickingHorse (Golden, BC) may be a decent option, the Eagles Eye restaurant at the top is stunning and as close to "fine dining" you can get at the top of a ski hill, you could get a slope side cabin with a bit more privicy, hot tub etc. There are a few nightclub/bar areas right on the hill that stay open till 2. Plus you are a quick day trip to Fairmont Hot Springs, or an adventure to Lussier Hot Springs.
Hopefully some others can weigh in and help you out!