I would add a point about consistency in big projects which is very important to realize: it's far more important to follow a not perfect convention than to make each single piece of code to be perfect but unique. So, it's not that easy to explain why we have to write not perfect new code just because we had decided to do so ages ago and if there are new and better approaches. Because it' s a way to survive. We have to follow our convention unless we make a decision to change it. And by having changed convention we should have enough resources to eliminate inconsistency between the current code and the new convention. Otherwise it's a road to the hell.

Nice post, by the way)