Leaving above ground foliage is great for wnter protection and helps trap snow for moisture. The pros suggest cutting back in early spring. Also the echinacea may do some reseeding for you. Kathy. Pix is Dianthus X. Loveliness. (yummy fragrance).
Plants don't "require" cutting back for winter... it's just something gardeners do for aesthetics (as last year's dead stems, though natural, are usually thought to look "messy"). You can just as well leave it until spring, also, and then cut off the dead stems. The standing stems help to collect snow, and also provide seeds for winter birds to eat. More importantly for me, I leave plants standing to provide some scenery through the winter, rather than a bleak landscape.
I think the easiest answer is, it all depends on where you live and what kind of winter conditions you normally have, if you live in a fairly mild area then there is no real hurry to tidy up your plants as they wont rock about when there are high winds, this does cause the roots to break and therefore cause the plants to weaken and MAY cause disease to enter.
There are other reasons too like in a cold high rain area, there is a danger of slugs / snails using the dead /dying foliage / leaves to become a place for these type of pests to hide and then lay eggs which in turn means that come spring, when everything is awakening, even the baby slugs / snails, these eat the young tender new growth and cost the plants to struggle to stay alive.
If you live in an area where there is a nice crisp winter and your garden is a picture of winter wonderland where the tree's, shrubs and plants get that beautiful frosted look like someone came along and painted them white, it is truly wonderful to be able to wait till spring and then do your tidy up as the frost will have killed of a lot of the pests that attack your hard work and eat your plants, but also when the thaw starts, you end up with slimy foliage that still requires your attention.
In these circumstances I would find it easier to tidy end of autumn and then in spring just have the soil to clear from weeds etc, but to be honest, everyone has busy lives and I would say, make the tasks right when it suits you AND the needs of your plants, there is no use moaning you have lost a lot of your plants because you could not spend an hour a day to help your plants survive the winters you have to live with but, go with what you know works best for you, just keep an eye out for any problems that come your way.
Good luck. WeeNel.