I like the idea of engineering some of our human faults away. I'm very concerned about how society will be run when transhumanism becomes more of a thing. It will most likely just be an option to the well-off in the beginning. The problem will be the transition. People who are well off and have made it have delusions and bias that interfere with empathy. What does this mean when they transcend? Will they give a fuck about anyone else when they have such newfound power? A common theme in humanity is that the tyrant frees himself and enslaves the people. This bullet needs to be avoided. Personally, I'm optimistic that such a movement will be more democratic and widespread, but people need to keep these questions in mind.
The ethics of the situations is pretty important, as well.. What if some old human hubris is still left behind, while a few engineering tweaks changes the person into something unpleasant.
Reminds me of pyschopass where an executive was transforming himself. He couldn't get the same high as before so he decided to hunt people for sport. Kept his mind clean. These questions are all being asked in the movement itself currently, so as long as people keep themselves honest, I'll keep my hopes up.
Oh one more thing. What if the machine intelligence and brain intelligence are found to be mutually exclusive, despite current predictions. WTF are people going to do when the hopes of transcendence are dashed by one simple fact. You won't be you anymore.