From a discussion in #1473 comment

It would be convenient if we have multi-dimensional reindex method, where we consider dimensions and coordinates of indexers.
The proposed outline by @shoyer is

• Given reindex arguments of the form dim=array where array is a 1D unlabeled array/list, convert them into DataArray(array, [(dim, array)]).
• Do multi-dimensional indexing with broadcasting like sel, but fill in NaN for missing values (we could allow for customizing this with a fill_value argument).
• Join coordinates like for sel, but coordinates from the indexers take precedence over coordinates from the object being indexed.