I really do think that SV went massively downhill after S3 which is why it's the cutoff point for
old_school_clex. Covenant is a really good episode and really it can be seen as closure for the series if you think about it
1. Clark gets sucked into the cave wall where he could easily come out as Superman in a few years time
2. Lana goes to Paris and could quite easily have just stayed there
3. Chloe gets blown up which explains her absence in the comics (I don't care what people say YOU SEE HER GET ENGULFED BY FLAMES IN THIS EPISODE. SV really is king of retcon)
4. Lex obviously survives being poisoned but the attempt on his life coupled with the end of his friendship with Clark pushes him to being the villain we see in the comics
See, it works!
( Covenant screencaps )