[averagewall]

More exciting is that the mol and Avogadro's constant will be pushed off to the side on their own. Hopefully an even more future update will remove them entirely. They're really quite redundant and pretty much only exist to facilitate the needless presence of the non-SI mass unit, the unified atomic mass unit, which thankfully will now be defined in terms of the kg instead of having two independent mass units like we have now.

[Pulcinella]

The mole and amu's (similar concepts) will never go away. It's a fundamental concept in chemistry. Reactions happen between individual particles but counting out individual atoms or molecules to supply for a reactions is impossible or ridiculously impractical at best. So chemicals have to be measured by mass (which we can measure) and then converted into number of particles. Until a molecular counting device exists, the mole will remain.

[averagewall]

It won't go away for the same reason pounds and miles won't go away - people who know it can't be bothered learning something new, and people who are learning it aren't influential enough to cause change. Avogadro's constant is not in any way fundamental. It exists to reconcile the two different mass units that chemists use - gram and amu.

With the 2018 SI change, Avogadro's constant will be defined as an arbitrary number without any physical basis, and the amu will be a constant multiple of the kg. No more 1/12 the mass of carbon 12.

Of course we'll still need a way to represent large numbers, but there's no fundamental reason it has to be such a complicated number. It could be exactly 10^24, for instance. Again, I agree this isn't going to happen because of legacy inertia.