Tim's last book tanked completely because of the creative team. Fitzmartin's writing was terrible, her characterization of Tim was so completely off base as to be laughable. Add to that the art style used by Rossmo...even if no one knew who he is, the preview pages turned off people (that perhaps weren't already turned off by Fitzmartin's out of character writing and out of left fiend interest in Bernard who quickly became a hated character.) I love Tim and tried to get into the book. It had some good concepts, I thought. I loved him living on the boat in the harbor and the potential supporting cast that presented, but I just couldn't get past the art and terrible writing.
Young Justice didn't sell that badly, but when compared to the page rate Bendis requires, it's sells didn't justify it continuing (and quite frankly Bendis struck out almost completely on his DC attempts with the exception of Naomi and I have to wonder if that wasn't more attributed to David Walker as co-writer and Jamal Campbell as artist never hurts anything.) Likewise, Bendis' poor attempt at renaming Tim with "Drake" was laughable and apologies to whomever designed that costume...but it was just bad.
Given a writer with interest in the character and ability to tell a coherent story (with art that isn't brain damaging) Tim could be a viable character again. Zdarsky is doing a great job with him in Batman and I could see him doing something great with the character if he chose to do a solo Tim story. There's plenty of others who could and would probably love to I am sure.
As for what to do with Tim...he's still got potential as a costumed hero, but he definitely needs a new identity and costume (better designed than...Drake.) His jaunts around the multiverse looking for Bruce would make him an ideal candidate for a 'road trip' with Connor (and throw in Cassie as well...she needs a home too.) Make them the new Challengers of the Unknown.