I've been thinking about ID abilities, and why some IDs are played far more than others. Yes, some abilities are just bad or undersupported, but I think there's a useful categorization that can clarify things.
I'll define Offensive abilities as ones that further your own board state, or make building your board more efficient. The classic examples of this are Kate and ETF. Both are rewarded for building board state, and are relatively unaffected by their opponent's board choices. A defensive ability is one that reacts to or is triggered by the opponent's board state. Ian Stirling and Quetzal are great examples - powerful abilities, but completely out of the runner's control.
There are hybrid abilities too. Leela's ability triggers on score or steal, so it's both offensive and defensive. The same applies to Jinteki PE. These abilities are usually tied to agendas, since they are inherently more flexible.
The last category are setup abilities that give a one-time or flat bonus regardless of board state. Andromeda, NEXT Division, Chaos Theory, and Valencia are good examples of this type. These decks are usually chosen if your strategy requires a certain board state that you don't want to have to assemble through card draw.
What do you think? Is this a useful way to categorize ID abilities?