Based on my (6 yrs.) experience and my horns, I'd say yes, my cornet is easier to play than my trumpet. I find it easier to get a greater range of emotion out of my cornet. And my shepherd's crook cornet is closer to my face. I feel more intimate with that horn. A plunger mute is a breeze to use!
I don't know whether it's me or the horns, but it's easier to make mistakes on the trumpet, irrespective of the mouthpieces. In my capacity as 2nd "trumpet" in the local community band, I'm grateful the director let's me play my cornet!!
....Yes, I agree. Cornet is funner!
warm regards
cornetmike
o-iii-O
p.s. Curiously, my trumpet is a pro model while my cornet is a beginner's! Go figure.... :P