The logic is that you fish in The Frozen Sea, and catch fish for both Cuttlesteak and Gigantic Feast. That's a good balance, for smooth progression through to 450, because you aren't wasting too many non-junk catches. Of course you will catch slightly more junk, so I see that it might not feel that way.
The reason it's like this is historic: It was a lot more important before patch 3.3, when very few recipes took you to 450 reliably, and most anglers would want to use a feast for the final 10-20 points of cooking. Even more important a year ago, when Northern Spices were harder to buy. Although I rewrote the guide for 3.3, I probably should have changed the emphasis, so that The Frozen Sea is more clearly an option, rather than the recommended path: The "single dish" and Wintergrasp options are very viable, and will suit a lot of anglers.
I suppose, right now, almost anywhere in Northrend is viable for those final few skill points, which inevitably makes a single method hard to agree on.
Added: Looking back through the numbers, I'm inclined to agree with you - there really is no need for The Frozen Sea option now, particularly once we consider the hassle of finding the meat, buying extra recipes, and so forth. Thanks for the suggestion. I'll try and re-write it with the patch 3.3.3 update.
