Oh yeah, tried and tested worked flawlessly for Ancestors Legacy, which is literally CoH with swords.
Let me use an example here:
SC2 was very lazy continuation to SC1 with barely anything altered or added.
SC2 coop commanders is what could be the direction, with more sub factions and interesting perks.
Instead they just copied all of SC1, changed 1-3 units depending on expansion, refreshed graphichs(which still was dated already the day it released) and called it a day.
A minimum effort was put into SC2 multiplayer compared to SC1, but there was still something new to play with.
WC3 is just lazy texture swap and probably some QOL changes, no one wanted that, no one gave a shit, people wanted actual continuation with either new factions or current but enhanced with new/different units/mechanics/heroes/maps.
Only most nostalgia driven drones will be fully content with "new" WC3 instead of WC4.
Its not going to be a game to bring in new players to RTS genre, its a lazy fan service for people who can't let go off nostalgia for early 2000 years.
Sadly, RTS as a genre is dead and blizzard wanted easy buck here, which they will get with their cult-like followers who will swallow everything as long as the logo is on it.
That includes lol Diablo Immortal.
Where the hell do you see CoH's cover and suppression systems at work in pseudo-medieval times? Plus CoH doesn't have melee, instead it has tanks, artillery and so forth.
I played Ancestors Legacy and literally the only 2 things both games share are the squads and retreat mechanic, nothing else. Flanking isn't really something CoH is unique for since many other games like the Total War series have it as well. But I will admit I am part of the crowd that compared to game to both CoH and Total War, I actually liked the concept of a hybrid game but it turned out to be a huge disappointment, but then again something like this has never been attempted before, taking CoH's squads, base building (sort of), retreat mechanic and Total War's formations, melee combat and scale (again, sort of) and combining them. So no wonder it failed, it was the first ever attempt at something like it, maybe they'll learn from it in the future, maybe not, hell if I know.
But I don't think it's a fair comparison, Iron Harvest is however since both CoH and it feature infantry, weapon teams and vehicles, mechs in IH's case and tanks in CoH's case, cover system, retreat system and so on but at the core, they feature the same gameplay and mechanics so apart from graphics and era, they're almost 1:1 like Supreme Commander is a spiritual successor to Total Annihilation, even tho a lot of TA veterans say they don't like it I still do.
As for StarCraft specifically, I played little of the original but I couldn't stand it's ugly 2D graphics and sprite animations, same for AoE and AoE2. But regardless, in my opinion StarCraft 2 did a lot to improve, sure they used the same base design for the factions and overall game but both games play differently, and it becomes even more obvious if you try out the Mass Recall mod for SC2 where you can basically replay the original campaign ported over to the new game which is fantastic in my opinion. That's another point, modding support, StarCraft 2 allows for more, bigger and an easier time to distribute mods and custom maps compared to the original, plus you could also use the game to play in third person for example thanks to the 3D graphics.
And lastly about WC3 and it's remaster, I never really played WC3 because while the craze for it was going on even in 2006 I was busy with CoH instead and I would say that maybe they don't have any other new ideas or don't see how they could improve upon it, or maybe they're just too scared to make something new as to not ruin the series like how DoW3 did.
IBM also sold it's hardware part of the company back in 2005/2006 over to the Chinese, which now basically sell the same laptops albeit a bit changed and under a different label, my dad says is because they thought they couldn't improve it any further and enough was enough, in which I see some sense in.
You can't force people to be creative, love or have fun, if it doesn't come naturally to you then it might be a better idea not to do it at all unless you risk losing a lot which is what I think Blizzard did and is currently continuing to do.
So in the end, I don't see anything wrong in sticking to your guns, if you're good at something keep doing it, if you wanna try something new but see that someone else already tried and failed perhaps it's a better idea to experiment with something else or take a different route to achieve the same thing. Easier example is Team Fortress 2 and it's "clones", namely Overwatch, which unironically happens to be developed by Blizzard, Dirty Bomb, which is somehow still alive as well as Plants vs Zombies: Garden Warfare which I still think last reported still had fairly populated servers running.