Are there any easy custom game platforms such as old Blizzard RTS games?

In the old Blizzard RTS games like Starcraft: Brood War and Warcaft 3, you could create custom games on top of the RTS platform. I'll bet there are many programmer here that might have gotten their start there. I grew up on Starcraft: Brood Wars myself, enjoying making games that didn't go far.

With the new Warcraft 3: Reforged editor having an EULA that declares everything you make belongs to them, and they do not have to compensate you for using your creations in anyway. Seems they're a bit bitter about losing DotA2.

I was wondering if anyone here has come across a platform that is similar in quality. I've experimented with a few in my past, but nothing that drew me in like Starcraft did.