"Sequels to the original 65 episodes"?
I agreed with most up until that part, seasons are supposed to build off of each other, not birth like spin-off's of each other.
Twilicorn season is like that, a spin-off of the original Twilight if she were a princess. It's not the same as the original of course, but that doesn't mean everyone has to panic and cry; I think it's an interesting take and I'd like to see how it works out.
It did seem very sudden and spontaneous, but definitely not too soon. Three seasons is plenty time to milk Twilight's (Oh my gosh I could have worded that better) Ponyville lessons before a change-up. If they introduced the concept more gradually, I'm sure it wouldn't have made as big of a bomb as most of the community sees it as. But as a season finale, under-explained, spontaneous, last-5 minutes bombshell wasn't the best choice.