Hard to make proper comparisons, but in adjusted hashrate YaCoin is possibly bigger than FeatherCoin.
I quite like some of the ideas behind YaCoin. But it has a real sucky name (Yet Another Coin). Why would anyone wanna have such a coin? It's like YAG (Yet another girlfriend) - who would wanna have such a woman?
And I don't like your new "predictable N" idea. That makes attacks especially easy ...