When using the new system I have to admit I have always changed it to the Source Editor option, but one thing I've found is that all links to other potential pages will appear blue when editing a page, regardless of whether there is a page or not. As such, any incorrect link does not become red, and therefore not a correct link, until after the change has already been made.
Also, I have noticed there is no auto-complete option when using the Source Editor. If there were a way to reinstate this, perhaps it would cut down the number of incorrect links?