I agree-- osoto gari is the boss. And most styles of jujitsu/aikido/etc have a type of osoto gari. I have used it effectively.
And I agree that one has to adapt to the situation and not try to go to a technique, but if the opportunity arrives....
Some specific techniques are worth perfecting, where as others, you just figure they are just impractical. I have always heard great things about the foot sweeps, but have yet to master them myself.
And, I believe in the simpler the better.
By the way, I have found that most aikido does not work on the street like it does in the dojo.