lots of nyancoin was monopolized by the few big miners
It wasn't just that. When we were slowed down at high diff and low hast, that hurt the blocks per minute much more than the low diff, high hash periods helped. Look at
coinwarz. We are now ~60% more profitable to mine than LTC*, but were ~40%
less profitable according to the 14-day average. (* The chart says BTC, but the text says litecoin.)