I wonder... should we stick with four races or add more? Humans/Orcs/Undead/Night Elves is already pretty good balance. Burning Legion and Draenei could round it to six. Maybe add Naga (alongside and some sort of Old Ones' servant race to round it to eight?
The Legion was going to be a race originally but they cut them from development.
Its funny that WC3 and FT already feature those races in certain ways. Naga are pretty much a fully-functional fifth race in Frozen Throne, I remember they had some neat units.
Alternatively... take a page from WOW. Alliance (Humans, Dwarves, Night Elves, Gnomes) vs Horde (Orcs, Tauren, Trolls, Forsaken). Then Scourge (Undead and co under the Lich King) and Burning Legion.
It would be interesting seeing Humans >> Alliance shift, whatwith Night Elf units in place of High Elves. Imagine fighting a Knights-Huntresses combined cavalry force.
As for gameplay... I dunno. I would bring back naval units, naval units are cool. Perhaps deepening the RPG system of heroes, but no idea how. Perhaps take some cues from Dawn of War, like the squad system and terrain? Terrain definitively needs to be more important, fighting in Lordaeron terrain should't be same thing as fighting in Northrend.
I always like when WC3's story is praised even though the whole Arthas arc thing is yet another "Dark Wanderer" thing that Blizz has done in just about every one of their big three from Starcraft to Warcraft.
And Arthas was a faggot.
Arthas did nothing wrong.
I do wonder what would have happened without the Frostmourne corruption. Arthas was already kinda cray-cray even before the corruption.
He would't have killed his own father upon his return, but he would have probably been renegade as fuck.