The way to look at this is as a preventative warning. In 20016, if I tried to draw an arc in a 2mm, 2mm square with 100 sides, it would (kind of) let me… but the geometry it created would be… awkward:
Yes, it lets me draw SOMETHING, but the geometry gets rounded doe to the miniscule size and the results are not pretty.
In 2017, when I try to draw the same thing, I get a message, letting me know that it will not be able to generate the geometry I am trying to draw:
So, it is not that 2017 is less capable than 2016, it is just letting you know that it is not going to draw incorrect geometry from the start.