[Update #2]: Warcraft 3: Reforged has now finally been released, and it's unfortunately a bit of a mixed bag.
[Update]: Blizzard has now revealed that Warcraft 3: Reforged will be released in January 28, 2020!
Warcraft 3: Reforged is set to arrive later this year, bringing with it a whole bunch of improvements over the original. You can expect to see greatly enhanced visuals, support for 4K resolutions and a variety of graphics options, better online play, and perhaps most importantly for Warcraft 3: Reforged's longevity, a significantly improved Map Editor!
While not exclusive to Warcraft 3: Reforged, Blizzard is also working on rebalancing all of the factions. The end goal, as you might imagine, is to make as many heroes and playstyles viable in both casual and high level play. After all, seeing a Demon Hunter and Death Knight duke it out throughout the early game was fun, but not if that's literally all you ever saw!
In order to achieve this goal Blizzard has been releasing and testing balance patches for well over a year at this point. However, it would appear that they are now finally happy with the state of Warcraft 3's balance as they have just released the final major update before Warcraft 3: Remastered.
As you might expect from the final update, it's filled to the brim with balance changes, bug fixes and technical improvements. I haven't played Warcraft 3 in a while so I can't exactly say how good the balance changes truly are, but from what I can tell they are mostly focused on making late-game units more viable and interesting, and that is certainly something I can appreciate!
You can read all about these changes, as well as share your thoughts with the developers, over at the official forums.