I have never and will never advocate removing the European species from our garden beds, lawns, or city parks. First, it's a futile gesture. Genie + bottle. And since that gesture most often means employing indiscriminate herbicide, it's a non starter.
Second, while dandelions just don't hold a candle to native plant communities when it comes to wildlife support (adult and larval insects), I find GREAT value in other ecosystem services they provide. Here's a partial list:
1) Solid groundcover plant. We want layers in habitat gardens, and this takes up a layer most folks ignore. It blends in nicely when in a tightly knit community.
2) The nature of its habit / form means broad leaves help shade the soil, conserving moisture and preventing some other weed seeds from germinating.
3) The taproot helps open up compacted clay soil -- especially after construction.
Now, some studies have shown dandelion may be mildly allelopathic, reducing the ability of other plants to establish around it (its pollen may also be allelopathic). I'll take my chances.
And of course, we DO have at least one native dandelion species to consider.
The "problem" of dandelions is twofold: first, they look weedy because they most often occur in monoculture lawns or park spaces devoid of other concurrently-flowering species. This means they stand out like a sore thumb, an obvious affront to a highly-managed space that's held back from its full, ecological potential as a meadow. Dandelions are nature screaming to be set free.
Second, and on a more philosophical note, dandelions are evidence of our human supremacy and confront our guilt or shame over creating so many environmental problems. It's complicated -- we can embrace what we've done and move on calling our actions part of nature, or we can be aware of our mistakes and learn a complex lesson about how to do better in the future and / or address other species that are even bigger problems than the humble dandelion.
What's in a weed? A story of adaptation to be admired and loathed. A reflection of ourselves. A testament to our complex existence as stewards of life and our own hearts.