Most part of the 1-star reviews should be in the support section.
Problem 1: Users does not change 1-star rating for the plugins after plugin authors fixed the bug, but the average rating is decreased.
Example: "Plugin generate too many notices..."
Problem 2: Sometimes users put 1-star rating for the problem which is not connected to that plugin. But in many cases users will not come back to fix it.
Example: "I installed this plugin and my notebook exploded!!!!! DO NOT INSTALL IT!!!!!!!" :)
Problem 3: one 1-star rating can lower average rating pretty easy. For example we have 3 5-star ratings and average rating is "5". And if someone will put 1-star rating - the average rating will be "4". In most cases users use only 1-star, 4-star or 5-star rating. These three options does not represent the real UX IMHO. The rating should looks like a hill and not like a hole.
It is the major problems, all other are no so important.
Solution: If the user, who submitted review does not return to write back or change the review rating than maybe it would be better to have ability for plugin authors to submit reviews for admins to re-check it.
For example if admin re-checked review (and it looks more like a support than like a review) and the bug from review is fixed - this review could be moved and converted into support topic.
Or if admin re-checked the review and it is not appropriate at all than it would be better to delete it completely.
Solution 2: But if it is too complicated than there is a simpler fix for this problem - average plugin rating could be calculated based on rating reviews from the last two years. This could fix problem with old 1-star ratings, which are already fixed.