I disagree. These two actors work brilliantly off each other, and it was a real treat to see that prickly, multi-level dynamic develop throughout Series 8. What they were doing wasn't superficial or obvious, which may be just what viewers expected to find, so they stopped at "grumpy old man" and "bossy control freak", when there's so much else going on there. It's not surprising. Our culture is just starting to come to grips with the idea that it's not true that the only important relationships men and women can have with each other are explicitly romantic ones. Series 8 was an effort to delve deeper, to find something that easily eludes us: levels of affection and bonding that aren't based on sex. I attended a panel on asexuality at a con last year, where people self-identifying as asexual described the disbelief they encounter when they describe their relations with their SO's as powerful and passionate love that's just not expressed through sexual activity. Think about Slash fanfic, which creates explicitly sexual attraction (and action) between characters who, in their original fictional settings, have strong and caring friendships with each other but not sex (Kirk and Spock, an outstanding example of this Slash trope). An example of relationships based on non-sexual love and bonding that we do seem able to understand is the bond between soldiers who've been through war together, protecting each other and taking risks together. That could describe Clara and the Doctor, come to think of it: adventures are full of danger, like battlefields, and you can love your brother-in-arms or a gifted officer with great affection, trust, and loyalty (and efforts to help him be the best person you think he can be, not the worst) without being drawn to sleeping with him.