He has played 10 enough to keep things running well in this team should the unlikely event occur that both Ford and Farrell go down injured. His kicking and distribution are second to none and the when he does run out at, or switch to, ten, he maintains a cool head and controls the game well. Combine that with his knowledge and experience gained from training with the team through the whole competition and it should be a straightforward choice. Saying that, rumours are that Loz is staying at the team hotel.
I really can't understand the reluctance to play Slade at 10, especially from someone who follows Chiefs and see's how he plays on a weekly basis. Last season people were loathe to consider him playing at 12 because he had a 13 on his back for most of the season, despite the fact 12 and 13 constantly interchange during Chiefs plays. A player of his ability could make a good account of himself in any position across the backline but his skillset and experience (almost all of his career bar last season) mean he plays best at 10, in my opinion. He started at 10 for the first 2 games of the season, Sarries and Wasps away. We lost both those games and it seemed to be blamed on the 'experiment' of putting Slade at flyhalf instead of Steeno the fan favourite. Steeno returned to the position and we continued to lose to weaker teams with our depleted and wavering squad. Since then, not only has Slade been the backup 10 in every match he has played, but the games he has started at 10 (Bordeaux away and Leicester away particularly) he has shown that he has the quality and confidence that is needed to control the game and get the backline moving at least as well as I have seen it before. Along with his distribution and kicking from hand, he offers a running threat, carries well, puts in big hits in defence and is a confident and reliable place kicker. Slade surely has the Chiefs 10 shirt moving forward and it should be a huge boon for England to have 3 young premiership 10's of international quality, two of which can play well as a 2nd 5/8.