The new anime series has not been confirmed to be based on the manga and there have not been any seiyuu confirmed:
http://sailormoonlife.tumblr.com/post/26709034676/noPersonally, I would love for the new anime series to be based on the manga. I don't understand why you would feel threatened by a new version of the series, particularly one that follows the manga more closely. The new series doesn't really affect the old series. If you loved the old anime series - many Sailor Moon fans, myself included, do - then what would a new anime series do to that? Do you think that a new series would make you aware of flaws in the old series, of which there are plenty? (I love the anime but it has many, many problems.) You don't have to watch the new series if it really bothers you. But plenty of people like the original Fullmetal Alchemist anime despite the reboot anime series, or they like both the original anime and the Brotherhood series (which follows the manga more closely). A lot of people loved the Berserk anime and manga and are disappointed with the new anime movies; but I don't think their opinion of the manga or original anime series is diminished in any way.
And to be honest, I don't think you're an "original" fan if you only saw the dub, and only within the last year watched the original anime or read the manga. I consider the anime and manga series very different entities, but IMO, the English dub is a censored bastardization of the anime. You can enjoy the English dub, but don't expect everyone to consider you an "original" Sailor Moon fan; you're a Sailor Moon English dub fan, that's all. I do think it's strange that you'd find merit in both the English dub and the original anime and treat them equally, yet you have issues with a new anime series based on the manga. IMO, it sounds like you're self-imposing restrictions on your ability to watch the new series, when no such restrictions actually exist. If the new series is intended to appeal to a certain audience, then what prevents you from watching it? You can enjoy the series without the need for labels, regardless of where you come from or what experience with the Sailor Moon franchise you have.