Now that I am working within a specific cultural framework, and writing for even more for Prairie Shadow Protogrove's rituals, it's become even more complicated. I just don't feel comfortable inviting people to an Ostara rite that honors Demeter and Persephone, for example - it just feels culturally wrong. I don't feel like I'm being authentic when I tell my daughters about Samhain, a sacred day when we honor our Ancestors; our traditions are very Heathen, and to call the holiday by a Celtic name just seems disingenuous to me.
I'm certainly not trying to tell anyone else how to practice or what to call holidays - it doesn't matter to me! But this is how I personally feel when using the 'traditional' Pagan names, so I've tried to come up with some a bit more modern. Though I am very much a Heathen and very inspired by history and research at this point, I want to help my children see with a wider view; should they want to follow a different path of Paganism or even leave the religion but still remember special traditions from their youth. I'll still refer to the solstices and equinoxes by their scientific names, that's what makes those days so special, after all. We've always called Beltane 'May Day', which it is - we just celebrate it a whole lot more than other people here in the midwest. Lughnasadh has always been simply 'Harvest Festival', easy-peasy but a tad confusing when compared to the Autumnal Equinox. The difficult ones so far have been Samhain and Imbolc - I'm just not sure what language to use to describe honoring the Ancestors or praying for the spring without resorting to silly and trite-seeming epithets like 'Ancestor Day'. I have always liked the name 'Candlemas' for Imbolc, and connects it back to my youth, but I'm not sure that stealing Catholic holiday-names is the best way to go.
I think this will always be a tricky topic as Paganism as a whole continues to diversify; with some wanting to retain the standard holidays but wanting them to be more culturally appropriate. I continue to hope for the wide-spread adoption of more neutral terms, but understand that for many that compromises part of the magic of these names. Like so much of the work of building a religion, I imagine that as time goes on, these things will be figured out.