I have seen Finder is giving some issues. For me, it is working fine as long as I use Latin characters. Since I work with Tibetan, I was used to search for text. When updating to Yosemite, it stopped working properly. I have checked with various friends and all have the same issue: Yosemite indexing has changed from Mavericks.
So here is a description: letters of the alphabet are still indexed (like ཀ་ཁ་ག་ང་), but when they are combined (like རྒ་), Spotlight is the blue, giving no answer. Again, this used to work very well before.
I have tried reindexing, following Apple's suggestion, but no success. It seems to be related to the indexing method itself.
Any advice? This is a big issue as we are used to search with Finder — a feature that is normally powerful in OSX.