Mediumcore is becoming less and less fun, it has to be said.
The game is engineered to kill you often, and when you can lose hours of work just by being unlucky (like having mobs knock you off a ledge down a big hole), it's hard to grin and take it.
And in some areas (like jungle), losing your gear means you are trapped and can never get back to somewhere less dangerous. An endless death cycle can be game over for a mediumcore character.
I'll still go mc if the new server is mc only, but it's really, really brutally hard.