The reason it was dropped was because of lack of use. This is confirmed in the MS response to a Customer asking if it could be re-instated.
Posted by Microsoft on 1/13/2012 at 1:37 PM
English Query feature when introduced in SQL Server was not a popular feature and we didn't find lot of customers using it. So it was eventually removed from the product. We have no plans to invest in such technology so I am resolving this as "won't fix". You can look at the Semantic Search feature in SQL Server 2012 to see if that meets your needs.
See this brief article:
Microsoft hasn't said much as to why English Query was [discontinued]. One could speculate that it may be due to lack of interest or an inability to provide accurate translations.