The lineup is in fact not "weak". If AK and Larnach are healthy, they are above average bats. AK especially, he could be a 130 wRC+ guy if right and hitting near his ceiling. Gordon was an above average bat last year. Kepler/Gallo are lotto tickets, if one of them clicks that's a huge win, but with their defense if one of them even grade out league average at the plate, that's a good player.
Buxton - Polanco - Correa - Miranda - Healthy Kirilloff is the best top half of any lineup in the AL Central, and top 10 in the MLB. And we're not even talking about the impact Julien/Lee/Lewis could have this year. One more big bat would be a nice-to-have, and would put them more on par with the big juggernaut/top 5 teams like the Astros, but they don't need one more bat to be a top 10 offense this year. Hell, they were almost a top 10 offense last year trotting out the likes of Celly, Palacios, Contreras and Cave nearly every day in the second half.
The question isn't talent, it's health.