It's not bad to follow manufacturers recommendations. It just may not be best, depending on what you are looking for. If you want engine's very optimal power and efficiency (like I do), go for an early oil change, throw away the manufacturer's manual, and redline the thing once fully warmed up on day-1. That's how they build race car engines for maximal performance. For example, your pistons rings have to sit right and tight. Your only chance to that is with some WOT during the very firsts few miles. Follow the manufacturer's recommendation, and you already passed your window. You also want minimal wear from metals going around. Ideally, every engine would get inspected meticulously at assembling and there would be none. But since these are casted aluminum production engines, there will be a significant amount. You can limit the amount of damage though.
Sure the engine will still last you very long no matter what breaking-in procedure you follow. It will very likely be really reliable. These are Jap. But will it be as efficient as it could have been? If you want to extract every HP or get optimal fuel economy, etc. from your engine, then you'd have to go out of the norm. And the nice thing is that it's really not expensive to do so. To me, the early oil change price is much worth it. And the other good thing ... it's much cheaper than any other after market parts people put in to get more powa...
You also have to ask yourself what's in the best interest of the manufacturer here. All they really want is sell bikes and that their bike stay reliable during the warranty period. They don't care about the 2-4 HP you could get from optimizing things. I do. For having broken-in 2 car engines much differently (yes i went through 3 engines on a same car with ... unlucky circumstances), I can tell that the one that I applied this technique was much stronger than the other. It was also burning virtually no oil. I was really impressed by that. Most engine at least consumes a little bit of oil over time. My 2 other similar engines were. A little bit. I am sold on it.. from personal experience. Of course I have done so through 100s of engines.
I would also hold on mineral oil for quite a few miles. An engine needs some wear to loosen up a little bit. Again... for optimal efficiency. Synthetic oil is too soft on metal while breaking in. No synthetic oil will ever go in my machines before at least 10-20k KMs. Ok, for a bike, I may go with 10k-ish only.

Def. not before. Suggesting to put synthetic at 1000 Km is definitely not a wise recommendation IMO. You should run away from the dealers suggesting so.
I definitely listen up (nod and and smiled) to every step the seller was suggesting me to do when I picked up the bike. While he was saying to gradually start rev-ing harder at XXXX kms, I was thinking to myself ... sure, I'm doing this in 10-15 minutes from now after everything gets properly warmed up!
Of course this type of break-in procedure and early oil change go along very well.
Now, to each is own of course.. But it's good that people are aware of another way!

Peace!