Correct Answer: When a large amount of pages exist and the options are between using a single meta description for all of the pages vs. leaving them with none at all. so it is a good chioce to no use meta description?
For sure without a meta description, will be worse. How will look all pages indexed? with the same description taken from content???
I would alter the code so you have a different description for all your pages wherever possible, assuming you're talking about some kind of template system, php or whatever.
well you could add meta description to your most important pages and leave the rest without meta description, coz search engines tend to favor your main page most, so you don't actually need meta description for all your pages! This is if we are talking about 50+ pages, else it's advisable to put meta description to all!
If its not possible to write meta description for all pages then just copy two lines from content and make it as meta description. If google bot don't find any meta description then i can pick any lines from content, it can be links or anything else and display as text and that look really ugly on SERP's. If its not possible at all to write different meta description at all. then dont write anything at all. Its better than having same description for each page.
google ignores the meta descriptions for serp but the other will not ignore meta tags. it's better to insert your meta tags for the other search engines