As it stands in Thaumcraft 6, Taint just doesn't feel... well, like much of anything at all. It doesn't feel dangerous and is very easily bypassed, especially since it doesn't really have any lasting effects on the environment that can't be easily fixed.

The biggest and easiest way it could be improved is to implement the currently-existent-but-not-utilized tainted lands biome, so that when taint does crop up it becomes a potentially world-scarring thing you actually need to focus on combating, lest it become self-perpetuating. Additionally, it'd be great for visual aesthetics.

It is planned (but I have no idea when I'll get to it) to expand on taint in general, including fixing the very underwhelming current biome.