Horsepower IS important. Two things sell sports cars: performance and looks. If Honda can achieve the performance with 300hp, more power to them, but I think they'd have to get the weight below 2,500 lbs to do it and I don't see that happening. Which leaves horsepower.
I'm confident that HSC will continue the NSX's tradition of being better engineered, more refined, better balanced and better built than the competition. But that alone won't sell enough cars to make the HSC a success. Not at $100K, and probably not at $60K. The exotic looks of the HSC promise performance. A supercar that can't perform is like a porn star with erectile dysfunction. What's the point?
I'm not going to spend $100K to buy a car that looks fast but gets spanked by a $30K Subaru and I don't think many other buyers will either. The HSC is billed as a sports car, a two seater, paddle shifted, mid-engine, aluminum bodied sports car. It's not a touring car, it's a performance car. IT HAS TO PERFORM. I don't care how they do it - nuclear fusion, wind sail, anti-gravity paint, or good old less weight and more horsepower - but it must equal, and hopefully exceed, the performance of its rivals or it will fail.