I can see why Lampard wants to improve the GK and LB over centre backs. Some of these statistics are shocking.
If Kepa lets in two goals against Wolves, he'll have let in 83 goals in his first 2 seasons at Chelsea. To put that into context, it took Petr Čech 5 seasons and Thibaut Courtois 3 seasons to reach that same number.
Chelsea's defense is actually facing less shots than typical Chelsea teams of old did. Kepa has only faced 92 shots this season, which is actually 25 less than the 117 he faced last season.
In Čech's 11 season's at Chelsea he only had one single season where he faced less than 100 shots, 2009/10 where he faced 93. Courtois faced around 100 per season, with his lowest being 93 as well in the 15/16 horror season.
09/10: Čech faces 93 shots and conceded 24 goals.
15/16: Courtois faces 93 shots and concedes 29 goals.
19/20: Kepa faces 92 shots and concedes 42 goals.
Čech = 1000 saves from 1241 shots (81%)
Courtois = 281 saves from 398 shots (71%)
Kepa this season = 53 saves from 92 shots (57%)
Using that metric we can see that Kepa has faced the 2nd most difficult shots to save this season. Kepa faces shots that shot go in 1/3 times. But take the example of De Gea who faces shots that should go in 1/4 of the time. Easier to deal with. So Kepa faces hard shots right? There are keepers in the league who face similarly difficult shots: Dúbravka (Newcastle), Mcarthy (Southampton), Ryan (Brighton). Despite that, each of those keepers has saved a lot of those shots from going in. Dúbravka = 71% save percentage
Mcarthy = 69%
Ryan = 69%
Kepa = 57%