There is nothing wrong with being creative. However, by focusing on the creativity rather than allowing it to be a natural by-product of building a balanced team, you’re missing the point and focusing on the wrong thing. Think about it. Why is it that almost all of the sets on Smogon are a product of the later process and not the former?
Simple: The latter process is making a set to fill a niche you actually need on your team, and you are more likely to test its viability by play testing it on the team you built it for. The former does not guarantee this at all; this is why the vast majority of the time you will find creative sets with maybe an ounce of strategy and not a thought of team synergy or actual in-battle prowess. Every “overspecific counter” set, every dumb “gimmick attack” set, and every “wrong side sweeper” is a result of the process, and is bad because of the process’s shortcomings.
This is why the creative movesets thread sucks. We glorify those who found a standard, when it is by chance or not. We have a thread of people applauding each other when they post in it a “creative” set, which is exactly the opposite of what we should be doing. This double whammy of new set glory and encouraging creativity is exactly why we get a stream of new members trying to “break the mold” even well before they’ve learned about competitive Pokémon and the OU metagame.