Even in our most successful years, I didn't fall in love with Klopp or praised him as a saint. Therefore didn't take your post as a dig, honestly. It's just that there is so much incorrect information or information without proper context on him and / or Dortmund out here that it seems necessary to point it out. No question that you're entitled to your opinion (that's what a forum is about, isn't it) but your response is based again on a lot of either incorrect information or an opinion that you may have rather exclusively.
Dortmund's squad 07/08 that finished 13th was nowhere near decency, not to mention second (on paper) as you said in your previous post: Dortmund had finished as 9th and 7th the seasons before, and I doubt that you will find more than 10 football fans under the sun who had watched the Bundesliga at that time who would agree with you that this team was rated highly and just had a jinxed campaign as e.g. the squad Klopp's last season.
Secondly, as others have pointed out, we didn't have decent resources at that time. It was a shoe string budget with next to no net spending (€1.5m in the summer Klopp came; €4.5m in 09/10; €1.0 in 11/12 etc).
In fact, Zorc and Watzke had one obligatory condition for Klopp's hire: He was required to agree on working with players the club already had, adding only mostly inexpensive youngsters (either from the club's youth or brought in).
As for existing potential: Mats Hummels was brought into the squad on loan 6 months before Klopp arrived. He also found Kehl, Dede, Kuba and Weidenfeller in the squad from whom not all were rated highly (i.e. Kuba). 5 players Klopp inherited played a role in his further plans. That's leaves plenty of deadwood left in my books.
It's also a myth which I read somewhere on the Caf that Klopp benefitted a lot from our youth system. Schmelzer played in our 2nd team but hadn't been considered 1st-team worthy before Klopp arrived. (Fun fact: They had already scouted Schmelzer during their days at Mainz before it became clear they'd move to BVB.) Nuri Sahin returned from loan to Feyenoord because he wasn't favoured by Klopp's predecessor. Kevin Großkreutz and Mario Götze are the only inexpensive other BVB youngsters who followed one summer later (Großkreutz had to be bought back from from a lower tier club).
The likes of Subotic, Bender, Barrios, Kagawa, Lewandowski, Piszczek, Santana, Gündogan etc were all bought by Klopp.
Taken together, Klopp didn't just mildly overhaul or helped an under-performing team to reach their potential.
That's very far from reality.
I agree with those, however, who say it'll be a much tougher challenge to make Liverpool title contenders than Dortmund.