Doubtful, you often have very little space to work with and have to get your point across succinctly. You don't have space to summarize the field to get a lay person up to speed adequately to understand the findings of the paper. Some journals, like PNAS, now require a paragraph describing the significance of the work in addition to an abstract that summarizes the work. The significance paragraph is supposed to be aimed towards understandability by a broader audience.
I don't think eliminating length restrictions would be beneficial even if they are no longer necessary. You can already basically have as much room in a supplemental/supporting section in many journals to include extra data/methods if needed. But if you extend the main article people will ramble on and in my opinion it will make it harder to read the articles for the intended audience (other scientists) with probably only marginal benefit for a broader audience.
