I do agree with you somewhat. And I did agree with you when you said it, until the other guy pointed out the great branding it provides.
It has been watered down a lot.
I will say, iMessage is a well utilized example of an iName. Reason being--if you begin a new text message, the top of the screen reads "message". If the person is iMessage capable, it changes to iMessage. This communicates to you whether or not it is a free message or not. So as annoying as it is to see so many iNames out there, this one at least has a practical application.
Well I guess for this particular app the nature of it makes it more important to have the "i" than in some cases. As you point out you would like to know that the other person can use the same service or not. But perhaps it is the previous overuse of the "i" that made me cringe when I saw this.
Then they can turn it off, or perhaps there will be some sort of contact selections.
And then there's the whole read receipt thing. It would say if it has been delivered and/or read.
It will probably look at the other user's ability to use facetime. If they can use that then they can use imessage. Well eventually. I think right now facetime requires wifi but eventually it will be available over 4G. Well it can look to see if the user is elligable for facetime when on wifi.