from your link:
The metadata show that the Russian operators apparently edited some documents, and in some cases created new documents after the intruders were already expunged from the DNC network on June 11. A file called donors.xls, for instance, was created more than a day after the story came out, on June 15, most likely by copy-pasting an existing list into a clean document. Although so far the actual content of the leaked documents appears not to have been tampered with ...
There is no story here with alterations YET. Removing the source information/metadata is something hackers do to remove the tracks.
Also, from your link:
... The original intruders made other errors: one leaked document included hyperlink error messages in Cyrillic, the result of editing the file on a computer with Russian language settings. After this mistake became public, the intruders removed the Cyrillic information from the metadata in the next dump and carefully used made-up user names from different world regions. ...
Changing metadata is something hackers will do. None of this means that the actual hackers were Russian, though.
If it were you doing the hacking, you might very well use multiple levels of deception to obscure the original source of the hack. For example, you might make it look like it came from somebody else and then only partially remove the info to make yourself look stupid.
So, for example again, the original hackers could be a few people from Anonymous who like Bernie Sanders, but then they made it look like it came from Russian intelligence which completely distracts everyone from the original source of the hack. Some other very small leads to other possible sources may be so hard to see and the right resources won't even be put into finding them. Of course, I don't really care whether it was the Russians or the Romanians or Anonymous that much. I DO think that treating some things as foregone conclusions without understanding them deserves a little conversation but I do not expect any Clinton fans to change their minds.
So all this said, again, it doesn't matter that much. What matters more is what the DNC did. And none of the alleged metadata changes change any of the contents of what the DNC did to Senator Sanders.
I actually agree wiht you that the hackers probably didn't change much of the content of the leaks. Or else the e-mails would have been much more damning. Highlighting e-mails about officals discussing possibly leaking information that Bernie was an athiest after the primary was decided isn't all that juicy to me.
If they were intelligent they would have changed things in only a subtle fashion so it was still believable.
The DNC knew how the hack was done, there was no need to change any metadata.
We have evidence that was tampered with--it's value is zero.