Been using sheet mulching since my first permaculture class in 1991. Could not garden over 35 very large raised beds (approx 5' wide and 50' to 75' long) without sheet mulching. We use cardboard, newspaper, what have you that will keep weeds & seeds from getting light then cover with straw, old hay, etc. Starting all mulching in early Winter after plants have died down. The weeds which do come through the mulch are pretty easy to pull out. It works well with large-seeded plants. We start small-seeded plants in the greenhouse then plant into mulch. Slugs are a problem but I asked an older neighbor what they used and he said wood ashes. This will probably not work on a very large scale as you have to go around each plant with a light dusting of ashes and re-apply after heavy rain, but is very effective - slugs and other soft-bodied critters don't like to crawl over the sharp minerals in the ashes. The problem we have is mice eating root crops and do not have an answer for this one.
With the weather weirding, we're trying to do a market garden (Wrocklage Run Farm) with very little fossil fuel usage so don't plow at all. Our tractor is used mostly for hauling straw, compost, etc around the 21 acres and we hope to soon stop using it at all. I am currently looking for a way to use cover crops and ground covers rather than sheet mulching to keep down weeds, hold moisture, etc. so we don't have to keep buying straw which is baled using fossil fuels. With raised beds, crops which have to be tilled in won't work - we disturb soil as little as possible. As one of my pc teachers said "you can take soil out of a hole but you can only put dirt back in." So we need cover crops/ground covers which are perennial and can be used with other crops in them.
BTW, our farm is 3 yrs old and we're planting lots of food trees and other perennials. We're testing plants which might grow here in hotter, drier and (the same plants) in colder, wetter conditions. If anyone knows of "tough" food plants which will grow in what is now zone 5/6, please let me know. Our farm is approx 1/2 miles from our home which includes forest garden, solar elect, solar water, etc etc.