If other people have copied your information over to their own tree (with or without credit to you) and changed it in some way (i.e., assigned the information to the incorrect person or family, etc.), how has that altered your original tree? Your tree shouldn't have been touched because, I'm assuming, you have a copy on your computer, online, on CD or DVD, or maybe even on a flashdrive.
If they've incorporated your information into their own tree and used it incorrectly as described above, they've corrupted their own tree not yours. People exchange family data all the time and incorporate the information into their trees. People use the same data in different ways which has no effect on any other person's tree that includes the same data.
When other researchers see your work, chances may be good that they've also seen the trees you describe as a complete mess. When they see yours, however, they may pick up on the differences which may prompt them to contact you to clarify those differences. At that point, you can tell them you've done your utmost to make sure you have correct information about the correct people and done you due diligence to document each fact.
As far as critiquing my tree, it's my tree so what I do with it and the information I include in it is really none of your business, or anyone else's. If you want to critique it, that's up to you. As to whether I would listen or care what you think, however, the answer would be a resounding no. It is my tree, not yours. I think these sentiments would be echoed by many if Ancestry implemented some of the suggestions about Member trees you've mentioned.