What I said is true. Cryptonote can and is mined very well by AMD video cards. In a few weeks I'll prove it by releasing a xmrig AMD miner so that anyone that already has an AMD card can mine this coin.
As far as rewriting it, that will take all but a days work. So not really that big of a deal for each small change you make.
Nobody stops you from doing that, But GPU mining has not big advantage vs CPU mining in CryptoNight, so part where you say that those mining with CPU will be "left behind" is not true.
I quoted threads and technical documentation explaining it in details.
Yes, everyone can write miner for webchain to allow gpu, but it won't change the fact, that CPU mining will still be profitable, thanks to CryptoNight.