"Removed to improve them"? How stupid do you think we are to believe that a tool needs to be removed to be improved, especially by a company such as MS?!? We didn't lose our toolbar while MS made changes. Please!! You insult us!!
Robert, think of it this way. Probably 3 years ago a group at MS decided to replace the whole grammar checking tool with something "better". Maybe they decided to replace it because it was provided by a an external company who wanted to charge "too much"
for the upgraded version. So then, just like doing a home upgrade they went in and "ripped out" the code that existed in 2013. Out, gone, just like a gaping hole in your house when the contractor guts the bathroom during a renovation. This was done years
ago. Then they started rebuilding the tool but they apparently ran into problems so it was not ready for the beta test, then it was not ready for the release in September.
Think about this. You try to write the logic for even just one grammar rule. You have to find words, actually classes of words in specific combinations. For example, if you see the word "and" in a sentence, look for a comma between the word 'and' and
the previous word (or look for missing coma), then look for comma and word before that. When you translate that babble into program logic, mostly "IF" / "AND" / "OR" logic, with lots of execptions. The code has to be efficient, REALLY FAST, because each
of 50 or more rules have to be applied to EVERY SENTENCE and PARAGRAPH in a way that does not slow down typing response.
Saying, "It ain't simple!" is a massive understatement of the effort required.
On the other hand, I wonder if it would not be better if they did a rolling implementation. Figure out a rule (or 3 or 5 or 10) and roll it out in a monthly Windows update. Go back to work. Add a few more rules to the existing set, roll them out. At least
that way people get to see slow but steady progress from month to month.
That way real world users can focus on just a few newly implemented rules. If they see issues it is easier to report the error in one rule than in a dozen. And errors in newly implemented rules would be easier to spot.
And since no one has done the comparison in options graphically, where is what the Word 2010 Grammar Settings looked like:

And here is the same dialog in 2016:

Quite the difference ...
<EDIT>
.
Jay Freedman posted a link to this KB article
https://support.office.com/en-us/article/Select-grammar-and-writing-style-options-ecd60e9f-6b2e-4070-b30c-42efa6cff55a
The article explains that each of the check boxes in the 2016 grammar dialog actually controls one or more rules, for a total of 24 rules.
I hope one of the fixes MS implements is to make this clear in the dialog, ie add the rule descriptions under each check box
OR
better yet, give each rule it's own check box.