One thing most women's snowshoes do is they are narrower in the back, so more sloped. This allows a narrower stance when walking, as some women walk "tight" – not wide. Often the snowshoes do take in account for a narrower heel, but not always. If they have a back binding or heel cup this will be noted. Not all snowshoes have this. If all it has is a back binding of fabric or rubber, your heel size won't matter. A cup will be an issue for ladies with non-petite feet.
While snowshoes are rated often by weight, the type of snow is almost more important to rate when buying – in other words what type of terrain you will be using them in. Concrete snow allows one to get by with more weight on snowshoes than heavy, sinking snow – particularly if you are the one breaking trail. If you side hill or are doing more technical climbs you will want more crampons than for casual outings on flat or gentle rolling terrain. Especially if the area is blasted by wind and the snow gets icy. Few of the women's dedicated models will work best on side hilling sadly!
The MSR snowshoes are definitely not for everyone. They are loud on hard snow (you can always hear a person coming from far away) and they do require learning to walk farther apart. It takes a couple trips but after awhile it seems normal. Denali's have one advantage and that is in the tails. For hard snow I just use the main snowshoe. For deep "it just dumped" snow I slap on tails and have extra flotation for breaking trail. They are not weight dependent but rather terrain dependent I have found – and I like that.
It sounds like you had the MSR lightnings which do have a lady version but are not as adaptable, due to being similar to many main stream 'shoes. As well, with the Denali's backing up is not an issue nor is crossings snowshoes.
If you do walk with a narrow stance and find it tiring or causing over step while snowshoeing the best advice I can give is to constantly force yourself to walk wider – this will help with any brand and after a while you won't have to think about it.
PS: I had size 7 1/2 feet in high school. Went to 8 in college from wearing Birkenstocks. Until I wore Birks I had narrow feet. By the time I had my son my feet spread nicely and I wear a 10 now. Kids and age do that, especially if a woman lives in sandals (I wear Chacos almost every day). So if ya wanna get rid of them narrow feet have a couple kids ;-) Hehheh!!!!