In essence, it is this: in 2016 Romney would be able to choose what delegates are seated at the convention. The states would no longer do that. If Romney doesn’t like the delegates the people of a state choose i.e. they choose to vote for someone other than Romney, then he can replace them with those that are for Romney.
Now what that boils down to is, no matter what the people say, no matter who they vote for, the fix will be in. We will be turning into an aristocratic and not a democratic republic. All nominees will chosen, not by the people, but by a select group of elite which will tow the line or be destroyed. And the people...well they can vote for our guy or vote for the other guy, who has also been chosen by similar elites.
I'm sorry, but that doesn't sound right to me as it pertains to 2016. I think you must be misreading/exaggerating those claims. Is there a link to the specific rules/proposals anywhere?