Hehe, how interesting. That's the book my class uses. It took us almost a month to get this book from the publisher...
Anyhow, yes, the first edition was quite old (around 20 years or so?). My professor supplemented the book with his own notes, but he says the new edition (which is what I have) does do a better job, enough to swallow that one-month waiting period instead of purchasing the old one.
How "modern" are you looking for? As far as disconnections are concerned, it makes very good points as to where to place them strategically. But it does rely on some "old-fashioned" chemistry -- for example alkyne chemistry (which was big back in the golden ages) is featured in this book. Nonetheless, I think it's a worthwhile book that goes into some good details about the whole retrosynthetic approach. It's also pretty cheap (got mine for $65 CAD or so).
If you want a page or so scanned, I wouldn't mind :-). Any particular chapter?
Warren and Wyatt's other book (Organic Synthesis: Strategy and Control) goes into more modern chemistry. The two complement each other but serve their own purposes.