I think you misread- Sergey has lots of personality and motivational skill (he's a brilliant natural leader with an amazing sense of humor). The main problem with Sergey (told to me by several SVPs) is that he's so smart (but not wise) , 10 minutes into your well-prepared presentation he'll ask "well, why didn't you do it this other way? It's faster and simpler?". This will cause your presentation to halt, you have to waste a bunch of time epxlaning why that is a cool academic idea that won't actually work in the real world, and then everybody on the team is amotivated.