Why wouldn't they though?
Tim is labelled as the best Australian BB housemate, in it's history.
No shit you'd want to find the next "Tim"!!
In fact, there were a lot of comments saying how good it was to have Tim back, because all the housemates were so boring. It seems the producers are damned if you do, damned if you don't.
And, if those are the characteristics that make them seem like "clones" then I say good! You want diversity in the house. Nothing was more boring last season to have Caleb, Matt and Ed all in the same house, who were all branches off the same tree.
Variety is the spice of life. It's also the spice of BB.