Ekans is a slightly worse Growlithe so the two articles should be more alike. (Maybe that means Growlithe needs to be rewritten, though)
Jigglypuff needs Mega Punch early on but in mid-game it can use the low-demand Tri Attack instead of Body Slam. Double-Edge/Mega Punch aren't bad either.
Jigglypuff's Normal STAB and fast exp. track redeem its bad stats—not many Pokémon have a stronger Normal-type move (Flareon and Kingler, for instance, are weaker). The low speed is annoying though.