Most of you that even moderately is collecting achievements, has noticed that in the Empire category, the last level 6 is gather 800 achievements, but the maximum presently available is 729. This means that GF left this for future planning
Now, since the workshop limitless updates, there is an endless discussion of whether it makes a difference or not, and in what extent. I for one have not yet decided, future will show, especially in the wake if the new update currently on test server. One thing is clear: the update needs huge, huge amounts of crystal and gold.
So, suggestion: create a set if achievements, where one gets them by updates in the workshop, in the form: have one kind of unit / ship upgraded 5-10 level, level 1, 11-20 level 2, 20-30 level 3, have two kinds of units upgraded 11-20 level 4, two kind of units 20-30 level 6, three kind of units 35 level 6, something like that, you get the picture. And since many players already spent upgrading, the achievements will be ready to collect. The rewards could be obnoxious tax advizer and or crystal.