When it comes down to his legacy, I think it is mixed at best. The proof of the pudding is in the textbooking, and Business Matters is a great textbook just because it was written well by a good author. Innovations is much more mixed, being based too much on a native speaker model and amusing but basically useless for students outside the UK. More seriously, the methodology for learning those collocations is a real step back with stacks of made up sounding dialogues and gapfills. The legacy with non-ex-LTP books is worse, with mind maps and sentence matching filling up page after tedious page. I think it is the reality of teaching collocations that convinced me that motivation and teachability are the most important things for students who don’t need a particular kind of language right now, i.e. how you teach is more important than what you teach. To quote a newish book exactly on Teaching Chunks of Language:

“At the core of the Lexical Approach to learning English is the belief that ambitious students need to acquire masses of multi-word ‘chunks of language’. But the techniques and exercises characteristic of this approach do not furnish teachers with an adequate means of helping students remember those hundreds or thousands of additional, complex, items of vocabulary. Consequently, within the Lexical Approach so far, the student has been someone expected to row across an ocean in a very leaky boat, the teacher, frustratingly, has been given no adequate way of helping them. We hope this book will begin to change things for the better”

I hope so too, but as I’ve only just finished the introduction I’ll have to leave you with that cliffhanger:

“Will chunks of language suddenly be made interesting? Will Alex’s faith in collocations be restored? Will Jaime discover that both of his twin brothers are having affairs with his seventh wife? Find out, only in MET magazine!”