Batting at 8 requires someone who's going to be abit of a slogger. No point having an established batsman at 8. As for the bowling thing, obviously Patel's going to have a better average, he's played 84 games compared with Dimi's 225. Mascarenhas was only given a run of 11 games and then discarded, and I think he's a better player than that, and deserves a place in the side. He's just what we need down the order, compliments the stroke play of Prior and the slower batting pace of Broad and Swann perfectly. He can also be shifted around the order to make the most of the batting powerplay, like Morkel and South Africa. Dimi's not going to have a fantastic bowling average anyway, he's a holding bowler, bowling his 10 overs for 40 and just slowing the opposition's pace, Patel may take wickets but his economy is nowhere near as good. He had a good series with the ball against a poor South Africa side, but then was poor in India. I'd take Dimi over him at 8.
The fact is, Samit's not fit enough. Doesn't matter if he's a better player, he's been warned about his fitness on countless ocassions by Notts and England, but has done nothing about it, and actually allowed his fitness to decline. That's not the kind of attitude that an international player should have, so I'm glad they have publically taught him a lesson by dropping him, and stated the reason for doing so. Hopefully it'll knock some sense into him, and make him realise what he's lost.