Stumbled upon this article, thanks for reminding me that tomorrow never comes, it's always about today, today and today. :)
Wherever you are is the perfect place to start. Yep, you’re there! You’ve made it! Everything you’ve done up until this point has prepared you to take the leap into greatness. If you don’t believe me, ask yourself, “Can I start yesterday?” Nope. “Can I start tomorrow?” We all know that tomorrow never comes. All of your choices and actions reside in the infinite now, so you might as well get started on making your next good one.
Found this pretty interesting comic illustrating good ideas, bad ideas.
Summary, to determine if an idea is good or bad, is actually pretty subjective, there will never be an absolute good or bad idea, there is always a ground of people will either support your idea or otherwise.
For me, I would say all new ideas can be good ideas, it very much depends on how you put them into action and make things work.