It is a hard call. However, you probably wouldn't get the free-wheeling, owes nothing to nobody, rich SOBs that we currently have in office. The state party machines would likely put in well-controlled puppets. The parties have much longer memories than do the voters. We'd probably get something like Deborah Poritz, but held on a short leash; wildly liberal, but not allowed to do more than dabble in her personal interests rather than NJ state interests. The state legislature could always divert blame to the Senator, and run on the basis of recalling said Senator. Since there's so much blame to go around here, the Senators would probably have to watch their step much closer.
As repugnant as it appears at first glance, I think repeal of the 17th would improve things, even in NJ.
Direct election simply increased the number of people eligible to vote for a Senator. Otherwise there's been absolutely no impact on anything.