It’s not a failure. By your methods, all you do is put half (or more) of the Senate seats out of permanent reach of electing Republicans. Direct elections ensure that EVERY state has a shot at doing so, including even Massachusetts (Brown’s election would never have occurred with a 90% Democrat legislature).
Not necessarily so. In my own state, we have Democrats with a history of shamelessly purchasing votes from demographic groups, which has been enough to virtually guarantee re-election. Half of the State's population is in three cities, the rest throughout the State.
The result has been a Republican State Government with Democrats in DC.
Repealing the 17th would change that.