In many countries middlename (patronymic) is necessary part of person's name. Maybe it should be added in core model and forms? Field adding is backward-compatible, isn't it? We even must not make this field visible by default.
And satchmo has good model for contact's phones. Maybe it's good idea to add secondary phone field to default contact info form. It must not be even visible by default too and it's very common thing.
Of course, all such things maybe done via custom models/forms/views/urls, but they are so common and simple and changes in core will even more cost-effective (tons of custom stuff to make simple things for just every project sucks).
I can provide patches for these things, if proposal will be approoved.