I think a specially based set would be the best option because there are many more options. This goes well with risk and reward, running certain moves will give the risk of not being as effective against the opposing team. For example, running hp fire when the team you face has a heatran. Your set would be completely walled.
On the reward side though, running certain moves and providing the proper support for having those moves can prove to be very effective. Lets say we take the same example of hp fire against a heatran and your opponent also has a genesect that threatens your team. You know heatran walls your set so you have a dugtrio to trap and kill and after carefully setting up your psychic bug, you can take out the genesect. You could also run hp ground if your team fears heatran. This will limit the amount of pure counters we have and give us more opportunities to reap the rewards of good strategy/ potential sweeping from boosting sets.
Now, i'm not saying those were likely examples but i think it shows how having more options on the moveset can help cap4 more rewarding if supported properly. Also having the option between psychic and psyshock provides a risk and reward aspect.