I think it’s partly because (or, mostly because) you are experienced.
IMO Yii 1.1 had some steepness in its initial learning curve, and that of Yii 2.0 is not less steep because it requires you to understand additional concepts like name space, composer, bootstrap, … etc.
I’m contributing to Yii 2 itself and doing lots of OpenSource or toy-projects to feel it in action. Takes time but removes that bad feeling. 1.1 is still a very good knife and it’s not a wise idea to upgrade in some cases.