I just started using Word 2016 from Word 2010 and the spell check process is 10 steps backwards in terms of functionality. I agree with OP - the list of synonyms is completely irrelevant, at least as a default, and just takes up space. Also, Instead of showing a misspelled word in its context and allowing you to change it in the spell check box, you have to refer back to the document and change it there, which impedes workflow. There is no option in the spell check box or right click menu to make an autocorrect out of you common typos, like mnay into many. This was a very handy feature in Word 2010. The dictionary is markedly, markedly worse and the grammar rules are way off base. It's true, for instance, that multiple word noun modifiers are sometimes hyphenated, but that doesn't make 'public-school district' correct. All of this is wasting my time and affecting my productivity.

Vervaine: Kindly don't hijack threads where people are trying to get help just to vent your spleen. Furthermore, as noted on every page on this site:
so spleen-venting here is a waste of time. If you don't like the way something works, you could make a suggestion for a change at http://word.uservoice.com/.
Do be aware, though, that MS is unlikely to change a 'by design' behaviour that's been around for decades, is familiar to any experienced Word users and is probably how most users expect the program to work.

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Cheers,
Paul Edstein
[Fmr MS MVP - Word]