Don't see a new type happening - stuff like IVs would quite possible have to change (Hidden Power for instance relies on IVs in a big way), the balance that's more or less there would more than likely be unsettled, and so forth.
As for the name... well, there's always been some disagreements or mentions on how some types sound odd. But for me, I'm pretty much fine with Normal, tbh, even if some of them are far from it. Thing is, where else exactly would they be put under then? Seeing as a large number of them don't use any 'elements', like Fire-types do, or have a characteristic, that would class them in the Steel or Fighting groups, normal for me is for those without such things. That's how I interpret it anyway.
Just randomly grabbing the examples in the first post: Porygon's a digital Pokemon - doesn't really fall into the others. Castform changes form and type according to the weather, but begins as a Normal type in normal weather conditions, which makes sense to me, and Ditto also doesn't really fall into any other group, IMO. It changes into any other Pokemon upon using Transform, but until then has no different element or anything that it can use. (And arguably, it's flubber-like shape is what it, ahem, 'normally' looks like until it changes into something else - that's its base form.)
Don't see an actual official name change either - the type names are pretty much set already, and given all the years they have remained what they are, they'll probably stay like that. But talking about it hypothetically is fun, anyways. -_-
