There are a number of thoughts on this matter. One concept, is that the book should be left alone, as it reflects the skill level at the time of release. Another is that any and all errors should be corrected. Somewhere in between exists reality.
For the Terran Chronicles saga we have expanded the team to include a finishing editor. Thus we have a storyline editor, a group of test readers and now this finishing editor. After I finish writing there are eight people that review my work. For my first book, 'First Contact', we only had a team of about five, and the process I chose to follow caused us to miss opportunities to capture errors. The more people that get involved the slower the process moves. At the same time the individual perspectives come forth, as each person offers their own opinion.
Every writer should aim at producing the best they can. If this means adding to the pre release team, then do it. If this means taking an eBook, and re-editing it, then do it. The long term benefits are that people are more likely to take you as a series writer if you admit to flaws and fix them. For an indie author who is trying to make their mark this is crucial.
During this time sales may dip as the focus changes from selling to revising. If this happens, accept it. I for one did not push my book on any market during my revision process, and it took four months. Once the work is done, and the errors have been corrected, the work improves in quality. Is the work now perfect? Will readers find something that was missed? Time will tell. But the work is now the very best that it can be. The true test will be the readers that purchase the work.
Revisions are fine, as long as they do not change the story. Any story line change should though about very carefully. Consider the positive reviews, these folks enjoy the story as it was.
Take it easy mates.