It became a problem for many in 2000, which predates when it started truly favoring Rs, I believe.
Either way, I'll repeat the refrain I often recite on this subject: if someone were designing a system of government from scratch today, they would never use this system; its a relic system that marginalizes the voices of everyone who doesn't live in the 6-8 states who are close to the tipping point.
I am envious of all the Michiganders on the board who live in a state where the vote matters... unless oft-predicted changes in voting behaviors happen where I live, my vote will continue to be irrelevant. Thanks to this system