Wait, what's this half that stuff that the druid can't do now? Maybe skill challenges, planar travel, and surprise rounds. Social encounters possibly too, if diplomacy isn't sufficient. That's a lot less than half.
Edit: Also, I think that standards are generally lower in a core context. If you're defining a list of stuff that a tier should generally be able to do, you've gotta be working in a particular book range in the construction of that list, because the list changes based on the book range. In that context, it's notable that planar travel and surprise rounds enter the druid's wheel house pre-17 out of core, and there's ways to do some stuff you'd want out of skills without too much effort involved. Y'know, stealthiness and skill list expansion and such.