Hello mcliquid,
Romanian doesn't usually change the spelling of German names, only for some old well-known cities that have had a historical connection.
I had read more about the "Multilingual names" in OSM and it seems that it is not a good practice to just repeat names in every language if it is not translated in any way, so you are right, this is not the most correct way to tag.
The Maproulette challenge has been a little confusing, it is giving you suggestions regarding the correct spelling in Romanian and I just accepted the suggestions for all the places that are spelled like that in Romanian (even if this means not changing it in most cases).
For Vaduz I would argue that there is some added value as Romanian "Vaduz" is pronounced differently than German "Vaduz"