I totally agree, 4 years is worth the wait.
I can think of one slight advantage of holding the WC every 2 years and that is, sometimes a player gets injured in early in a WC, and competes again 4 years later, he could be past his best. So if it was held every 2 years, the player would only have to wait another 2 years, and he could still be at his best. It sounds confusing, and it may not be a great argument for hhaving it once every 2 years, it was not my thought, I read it somewhere, but I took note of it.
But anyway, I personally think that it should stay once every 4 years, I already hype up every 2 years when football at least European football is at it's highest level, should the WC be held every 2 years, we would have a major tournament every year, that would be too much for me to handle, I don't think I could watch every match on TV anymore, as I'm still trying every time to watch every EC match and evry WC match.