Many of the Democrats' most shocking losses in 2016 were in the Midwest, most notably Pennsylvania, Wisconsin and Michigan.
Klobuchar has sensibilities that both appeal to those in the Midwest and provide a contrast to Trump - she is calm and rational rather than ostentatious. She does not play Trump's game of name calling and anger: she is above it, without seeming elitist. Klobuchar even has policies aimed specifically at farmers, something lacking with other candidates. She is extremely popular in her home state of Minnesota, and this popularity will translate across the Midwest and win key states for the Democrats in 2020.
While Klobuchar may appeal to the Midwest, there are considerable sections of the American population that she does not appeal to. Her strategy focuses hugely on winning the 'white vote', without much appeal for people of colour, a vital voting bloc for Democrats. She also does not appeal to the further Left of the Democratic party who prefer candidates like Sanders or Warren.
[P1] Democrats have suffered major losses in the Midwest. [P2] The Democratic candidate needs to fix this. [P3] Klobuchar's popularity and familiarity with the Midwest make her an ideal candidate.
Rejecting the premises
[Rejecting P3] Winning the Midwest does not automatically win the election for Democrats: there are many other voting blocs that need to be appealed to.