We do actually support filters in Vue 2. We added them back for v-bind and moustache interpolations. If you want to read the long discussions we have about this, you should be able to find the issue on Github quite easily by searching filters 2.0
At the moment, we're very careful about adding new features, we take into account the amount of code needed to make it work because it means a bigger lib and also more code to maintain. We also think about how it affects existing features. For example, we try to avoid adding multiple ways of achieving the exact same simple thing because it may be confusing for newcomers.
So we try to keep Vue easy to use but powerful by providing warnings whenever possible (that are stripped off in production mode) and by keeping the API surface small. Although it may be a bit too large for v2 at the moment