Gremlin is gone, but he was not the only one who would delete threads. If this feature were restored, people would definitely be deleting threads they start and then turned ugly. This has happened many times in the past.
The problem is not that the deleter's posts are gone....but everyone that contributed to the thread also has all of their posts deleted, and not by their choice.
The ability to modify your own posts is adequate. You should not have the ability to change or delete someone else's posts, as you would if you deleted the whole thread.