Henning, I see, for Germany sometime the last word is "strasse" so it would not be useful... but the search by full street name should be almost fine right now.
Carlos, not sure about Spain - I agree it can be sometime restrictive - "Calle Naciones Unidas" is an example but if one knows that searching by last word is possible, beside the full street name search, I believe it would be extremely useful.
On the other side, having the index built for each word, as it is supposed to work in 2662, would really be the final solution if performance of searching is not heavily impacted, as I suppose.