This is a serious red flag for the future of the site. If anyone wants to catch the great Reddit exodus of 2016, start building your competitor right now.
She's also one of the best consumer-product operations people I've ever met, and generally brilliant, honest, and helpful. While I know a lot of YC founders, partners, etc., Ellen is the person I'd go to for advice about whether a product/company direction is a good idea or not.
Bringing a founder back is great, but Ellen is amazing in her own right.
I think that makes up for her being a former VC :)