I mostly want to build a team of pokemon with sp. attack and speed as their strong points. What's the best choice of pokemon and their nature?
Kind of bad focus to build a team around...
Can't you have a balance between physical and special sweepers? Your choices pretty much limit your ways on countering other Pokemon.
He didn't ask what you thought of his focus. He asked for Pokemon suggestions.
Alakazam and Gengar are always good choices, both with Timid nature. Alternatively, you can use Espeon with it's hidden ability Magic Bounce instead of Alakazam. Also with the Timid nature.
Is this for a competitive team or an in game team?
@FrostyGaga; I see no reason to give advice on a team that is evidently going to fail. There is no point to helping him walk towards the path of sharp things before helping him roll across it. Anyway, your starting suggestions are almost entirely null since you can't build a decent team around a core of Espeon and Gengar without them being there for a purpose.
@LucarioBlade; The easiest way to build is to find two win conditions and then aid yourself in achieving them.
You have no idea if the team will fail. You are assuming that it will be a competitive team for some reason. If it's ingame or casual, he can do just fine and more with a super specialized team. And even if he wants to use these competitively, what's the big deal? I'm sure he knows the consequences of a restricted team like the one he wants given that he didn't ask you or GD to elaborate, which I think a player seeking advice on a good competitive team would do.
And no, my suggestions aren't null. I never suggested a "core". I'm just doing exactly what the blog entry asked; suggesting Mons. Instead of, say, telling him how uncompetitive his team would be.