I read somewhere that it was to reduce the weight of the reasoning from 2/3 as it used to be, down to 1/3 of the test. The rationale being that the reasoning is the most tutorable aspect of the test. There has also been a lot of criticism in the past that the test is too maths orientated and therefore those passing reflect only the top 25% of maths students and some very gifted children were slipping through the net.
I think the new test is good, as it encourages a well rounded education, even if you are tutoring. Also, hopefully will encourage schools to work to a level too, as it will be noticed by parents if lots of children are failing on one paper.
I also think it may have something to do with the fact that many children had got through the old test with very high scores to get to super selective schools, once they were at the schools it was apparent that the English levels were quite low and the children needed extra help in that area. One head teacher actually said in their speech that they were having to give a lot of extra support on English.
By introducing the English and giving it equal weighting to maths and reasoning, they are aiming to get a rounded selection of children (tutored or not!)
One head also told parents that if you had tutored to get your child through the 11+, then be prepared to tutor for the whole time they were at grammar!