I spend much of my time improving articles on a long-established site. Most of these articles are already long - 1000 to 3000 words - with multiple images.
The improvements are usually adding a new section to beef up the length and give the article relevance to a new suite of keywords or make it relevant to topics in the recent news. Do these help the rankings? If the site is already near the top of the first page for the root query, it usually doesn't. If it is deep in the SERPs at position 50 to 90 it usually does.
Regardless of how the ranking for the root keyword changes, these improvements often increase the traffic - because they expose the site to new keywords.
but then within the updated, shortened copy, integrating more target keywords naturally.
If you do a good job of this, I think you will get more traffic, and it might be a better result that moving the rankings up.