As it stands, specifying the direct X, Y, Z co-ordinates, for the most part, make the location task rather useless in worlds in general unless they are using a specific pre-made map.

Variants on this:

• Visiting a specific, specified biome.
• Visiting a biome that contains 1 or more specified types (HOT, SNOWY, etc)
• Visiting a specific Y location: going to the highest/lowest point available is already (partially) a quest with Thaumcraft, and it was requested specifically in #420.
• Visiting a specific structure: at least as far as I recall, structures store data about themselves in the chunk (i.e., as evidenced by the nether fortress advancement).
• Visiting another dimension.

Vague variants:

• Travel a certain distance away from spawn
• Travel a certain distance via boat
• Travel a certain distance via horse
• Travel a certain distance via a source of flight (elytra, hang glider, etc)

Of these, the two biome tasks have been implemented in another branch, but I need to merge them back into the main code base and test them more thoroughly.

Going off what was sent to me from my own request, this pretty much sums up what I was requesting plus offers more I didn't think of. This would be a fantastic feature.
This hits all the spots I cannot think of anything to add

Temporary work-around: using Triumph (without removing Vanilla advancements) allows you to create manual advancements that can provide triggers for most of the original requested modification.

As such, this won't be as high a priority moving forward as say, the break block/place block advancements.