Instead of choosing between gulp or grunt, you'd need to choose which config flags you want for this hypothetical "gunt". So instead of having simple to use tools (but a bunch of them), you have a few tools which take weeks of learning before you can even scratch the surface on them. And it leads to tools that have settings that nobody knows about because nobody uses them, and weird security holes and issues because of legacy support for an option that was added 3 years ago which when combined with a new flag causes everything to break...
Gulp is very simple, it's like 4 functions, and like 3 or 4 "conventions" you need to learn. There is no config, there are no settings, and there isn't any baggage. And that's the theme with JS tools. Rather than bloating current tools, you make a new one. Switching between them is easy, as they are all very trivial in nature. The power comes from combining those trivial tools.