Na.. they covered that in the twitch http://www.twitch.tv/swtor last week.. you will not only have access to your old companions.. but you will be able to acquire other classes companions. They went over it in minor detail.. so maybe they changed their mind from E3.

What im not clear on is when/how you get the access to your old companions, but they said you will be able to use your old companions if you want to.. as some people are attached to certain ones and the understand that.