this is gonna sound ranty, but it's straight from the heart:
i think most of them are pointless. not every feature needs to be a new keyword. stuff could be expressed within the language. if the language is so inflexible in that regard that it's impossible to express stuff without a keyword, use macros for gods sake.
why is there a need to have a "convenience func" declaration?
why is "didSet" a keyword?
what about "actor"? most other languages don't have nearly as many keywords and manage to express the idea of actors just fine!