Yeah, cause Heyward and Schwaber hitting .178 was so much better than some overrated .320 hitter like Goldschmidt or Altuve
It's kind of ironic you mention Heyward. I'm not going to be as dismissive of you as some but Heyward is the type of player who should be a high average hitter. He's putting the ball in play roughly 76% of the time and he doesn't strike out(13.3%). As an example, Altuve puts a few more balls into play because he walks less but last year he k'd at a 12.7 % rate. Heyward's BABIP murders him though.
What's interesting and I am gonna throw credit here at Chili is that the cubs are showing vast improvement in K rate. Batting average is effectively 2 factors, K rate and BABIP. K rate is just a straight malus to batting average. BABIP is effectively your hits. You can't really change BABIP. Some players will run a higher or lower BABIP than .300 but that's largely dependent on 2 factors. One is speed. Fast guys can beat out infield hits. The other is power. A guy like Bryant who will smoke line drives at infielders is going to have a higher than average BABIP. Basically no one gets faster outside of the normal aging process. You can add some exit velocity to help with BABIP by changing your launch angle but Maddon seems to believe that leaves you open to k rate issues and the stats seem to back that up.
As for the cubs k rate this year,
Zobrist - 13.1 %/14.8 % 2018/career
Heyward - 13.3 %/17.5 %
Rizzo - 14.5 %/16.7 %
La Stella - 16.3 %/12.4 %
Bryant - 16.5 %/23.4 %
Almora - 17.3 %/16.7%
Contreras - 17.4 %/22.3 %
Russell - 17.6 %/24.3 %
baez - 19.7 %/28.3%
Caratini - 21.4 %/20.5 %
Schwarber - 23.0%/29.1 %
Happ - 45.5 %/31.2 %(2017)
So, with the exception of Happ, La Stella, Caratini, and Almora everyone has seen their K rate drop. I think Rizzo is up from last year but that's likely just his poor start. La Stella and Caratini is likely a lack of playing time that will even out in time. Almora is still a very good rate but it's more because they are exposing him to more RHP this year. Happ clearly has some issues to work through. But as a whole that's a rather remarkable improvement. Last year the cubs had a 22.3 % K rate as a team. This year they are at 21.1%. If you exclude Happ's 99 PAs and 45 k's they are 19.1%. That would be #2 in the league behind the royals at 18.4%.