Oh, what a joy it would be if IP law was wiped away before the next CoH.
There is no IP law at play with Company of Heroes save for the title. It's not as if you are talking about Star Wars where only people with the rights to make a game can. If people want to make a WWII RTS they can, and have. If there was a large untapped market for this then others would fill it as well.
Relic make a good game and it's sold a lot of copies. 4 million+ when I was there and more since then. 500 people on a forum don't override the millions of copies sold. If you don't like it, fair enough. Nothing is so perfect that it couldn't be better. But the idea that there's some magical IP law preventing the game being made by someone else better is kind of off target. If Blizzard or anyone else wanted to make a WWII game they could. But like CoH2 it wouldn't be perfect. People complain about Blizzard games all the time.
If fans want to make their own game they can. Heck I'll donate $10 to any reasonably professional Kickstarter if you manage to start that.