Fair enough, you want the best for the England team regardless of the consequences to the concept of international football. I think it just feels like cheating though. Dangerous slope to go down as well, the logical step after that will be that you can pick and choose players as well as managers, and before too long you'll no longer be watching England v Spain in the World Cup, you'll be watching Man Utd v Barcelona in the World Super League, because there will no longer be any difference between club football and international football.
And I know I've not been accused of this myself, but seeing as one of the arguments often used against those in favour of England being managed by an Englishman is that they're nationalistic "Little Englanders" - I'd say my circumstances make me one of the more "Europeanised" (is that a word?) Englishmen on here, so it's not just Little Englanders that are arguing the case of the English managers.
And for what it's worth, even sticking to English managers, I still wouldn't appoint Redknapp, I'd go with Roy Hodgson.