Democracy is overrated, but not to be eliminated entirely, merely limited. A repeal of the 17th should include elimination of popular primaries, referenda, and canvassing w.r.t. Senate candidates. After all, democratization and corruption existed prior to 1913. Towards the end of the pre-17th period, if wikipedia is to be believed, some Senators were actually appointed by referendum!
You're right. But the corruption matters more now because the 17th amendment has made congress more powerful relative to the states.