I am not sure "chip on my shoulder" is fair.
What I do is look and read and see what water he has to say holds outside the context of who he is and what he has accomplished outside of realms directly related to education and children.
And the common sense answer always coming back to me is - very little.
To answer in true detail would take more space than is appropriate to take here.
What is typical in his writing on the subject is a good analysis of the issues - saying all the right things, mostly from other sources, about what our intent should be about children and learning proces and etc. and etc., and then part 2 is the presentation of his answers, but there is no coherent effort to connect the dots on how in any objectively, definable way his answers address those problems. Except that he is Alan Kay.
Bottom line, I think the questions being addressed can - at this stage - only be approached with a sense of humility. There are many who for example believe that exposure of children to computers as a learning mechanism is not simply overstated, but is fact actively harmful. My mind is open to the possibility that they are wrong. And that they are right.
Bottom line is that Kay consistently seems to me to fail the humility test, where that is the most meaningful test to pass in this domain at this time, in my view.