Here's a hypothetical scenario for you. Let's say you come across a dealer who is selling 1910-1919 wheat cents for $0.25 each and in bulk for $0.20 each. He has about 50 of them. You get home, search through them, and find that about 40 of them are one of two years and the other 10 are different dates. It's not the best selection in the world but at $0.20 each it's a good deal nonetheless. With the above, if the lot was described simply as "1910-1919 wheat cents", what would your review be? Take into context that at $0.20 each, the earliest mintmarked coins would be from 1916 or 1917. Based on a recent experience of mine as a dealer.
My review would be a positive one. It sounds like what I would expect to get in that lot, for the most part. There's certainly nothing inaccurate about it.
As someone who has both sold and purchased mixed date rolls I'm more inclined to believe that most people seeing the date range wouldn't be happy getting a roll that's ultra heavy in one or two dates. Personally when I see that kind of listing I hope to get a good representation of the full range of dates, not just a smattering and mostly one or two years.
With the description given I would not buy it and the price adds to that reason. The cost is too high even for early dates. I’d be willing to say that 1919 was one of the multiple dates. There is nothing wrong with the description but as a collector and a person that buys coins and sells coins in an antique shop the description makes me think.
You can't expect to get better mint marked pieces in a lot like this. You would expect duplicates. The main thing to be concerned about is cull coins which aren't much of anything. A coin which grades a strict Good is not a cull. Corroded and mutilated is a cull.
Surprisingly I don't see very many culls when searching through them. My most recent 10's and 20's came out of a lot of about 700 wheats,, most of which are anywhere from G-VF. I agree with what you said about better mintmarked pieces. Thankfully I haven't come across any customers who expect it but if they ask, I generally tell them what dates could be found. I also exclude 1915-(P)'s since those are a better date.
It would be better described as "lot contains 1916-1919" but I would not return/complain (maybe look elsewhere in the future if I was hoping for a better mix).
Already been searched because of the date range. $0.20 I guess isn't a bad price for an earlier date wheat. I can get you a better mix if that was what you were looking for and I'm Not a dealer.