All true, although considering the human is a social animal, being able to interact with and manipulate one other is important. And I think being clever is still great for the species at the moment as it encourages the creation and use of tools to make survival easier.
Edit: another thought, being bad to members of your own group may lead to expulsion or exclusion, losing you communal advantages.
by being clever you can end up painting yourself into a corner though. Look at us today, we're pretty clever, we have our medicine and electricity, but if our situation changes, we're screwed. I mean, Stephen Hawking is pretty clever, but if it came down to it, I'd eat him.
Being the fittest means everything until your situation changes, and fittest means 'best equipped'. If you were an animal that had to run after it's food, your species would favour the fastest runners. But if you exhausted your food and began to depend on food that lived up trees, the better climbers would prevail. So it's survival of the best equipped within your present scenario. Adapt, or die. 99.99999% of all the species that have ever existed have died out for that reason. Although 'died out' is a bit misleading, an extinction can be based on a species evloving into something else.
I think we are evolved to fit our situation. I don't think we need to be best equipped anymore, as it is easy to survive. When it changes, we'll have to change. We won't see it though, we'll be gone by the time it happens. Say we have a total nuclear disaster and pretty much everyone dies. That's not evoultion. The evolution comes after, and it's not based on skills that we remember before the holocaust. It is dependant on physical traits that help us survive. Figuring out things like how to build a water filter from whatever you can find isn't evolution. We already know that. Capacity to learn is not a new evolutionary trait for us. We already have the capacity to learn new skills, hell, most dogs have that. Evolution would be another step forward from there, and I don't know what it would be. I think we are slowing down in our evolution and the only way for us to see any increase would be to seriously dilute the gene pool and breed the fittest.
I think a valid question would be considering the advances we are making in technology, medicine, etc, if our situation doesn't collapse, where do we evolve to next?