Scientific Great Leaders are supposed to (a) increase science output, or (b) build great wonders, except (a) doesn't work.
The AI is not good at using armies, but that's not exactly a bug, it's just an inadequate amount of I in the AI with respect to military tactics. This is not a big surprise. It's not the sort of thing that AI's do well in any game. The only times I've seen an *apparently* competent AI was when the situation was highly controlled (a well-defined battle or scenario) and the AI could be scripted or designed specifically for the purpose of fighting that one battle.
The AI is not good at using armies, but that's not exactly a bug, it's just an inadequate amount of I in the AI with respect to military tactics. This is not a big surprise. It's not the sort of thing that AI's do well in any game. The only times I've seen an *apparently* competent AI was when the situation was highly controlled (a well-defined battle or scenario) and the AI could be scripted or designed specifically for the purpose of fighting that one battle.