I agree, but there are some episodes that have heavier themes or focus on God more. There's a (sort of) spin-off album called "The Truth Chronicles" and most of the episodes have a big spiritual theme. The Novacom and especially the Blackgaard Chronicles have a very heavy spiritual war. They also have a spinoff series called "Passages" where two siblings are transported into a different dimension, where they help Darius (David) and Fletcher (Gideon). And of course there are heavier episodes sprinkled through the archive.
And you do gotta remember that they are made for little kids, but the fact that they are able to tie Bible Verses to kid's situations for over 30 years, I find it impressive.
Sheesh, didn't mean for this to sound like a lecture
but if you are looking for heavier episodes here you go lol