Which do you prefer? Do you like having a variety of types or would you rather have Pokémon that can cover each others' weaknesses? I myself choose diversity over synergy because I'm not good with synergy and would just rather have type coverage.
Synergy = Diversity to cover weakness
Synergy is always a preffered choice in competitive pokemon.
As state, the two are not mutually exclusive. Synergy is actually the step above diversity.
Just having a bunch of random types, just as long as they're all different, is not the way to go. For example, I go with a Fighting type, a Normal type, a Ground type and an Ice type. I am now effectively unable to hit Froslass.
I prefer synergy, even if it's just basic synergy. They may not be the tightest unit, but they have to be able to work with each other, having something to at least cover their weaknesses.
Yup. Diversity kind of goes with synergy. A team needs to be diverse to have good synerygy. A team of all of one type will not have good synergy, and will not be diverse. A team of different types will be diverse, and will have good synergy if the right types are used.
There is not one offensive core. There is very many. Scizor + Lucario is a classic generic example though.I thought the DPP offensive core was Infernape + Lucario.
I really don't think they're mutually exclusive. In fact, they kind of go hand-in-hand. As a general rule, if you want to have perfect synergy, you're probably going to have a degree of diversity.