New Twiddle

application.controller.js

import Ember from 'ember';

export default Ember.Controller.extend({
  componentName: 'component-one',
  name: 'Ben',
  
  actions: {
    switchComponent(name) {
    	 this.set('componentName', name);
    }
  }
});

application.template.hbs

<strong style="background-color: yellow">This demonstrates a bug with component positional params. Notice the `name` value isn't updated correctly</strong>

<hr />

<b>Positional:</b> {{component componentName name}} <br />
<b>Named:</b> {{component componentName name=name}}

<hr />

name: {{input value=name}}
<button {{action 'switchComponent' 'component-one'}}>Component 1</button>
<button {{action 'switchComponent' 'component-two'}}>Component 2</button>

component-one.component.js

import Ember from 'ember';

export default Ember.Component.extend().reopenClass({
  positionalParams: ['name']
});

component-one.template.hbs

Hi {{name}} from component one

component-two.component.js

import Ember from 'ember';

export default Ember.Component.extend().reopenClass({
  positionalParams: ['name']
});

component-two.template.hbs

Hi {{name}} from component two

twiddle.json

{
  "version": "0.6.5",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.4.3/ember.debug.js",
    "ember-data": "https://cdnjs.cloudflare.com/ajax/libs/ember-data.js/2.4.0/ember-data.js",
    "ember-template-compiler": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.4.3/ember-template-compiler.js"
  }
}