No, you don't sign somebody with the intention of sacking him part-way through the season.
It seems that the Cats are at least trying to comply with the 5-man cap. Which means that Wagstaff, Jervis, Steindl, Vague, and Hire must be on collectively less than ~$480k.
Wagstaff would actually be on reasonable money, although he did take a pay cut with his last contract. Jervis wouldn't be on the minimum. Maybe Steindl. Vague yes, but not much left for the 5th spot.
So they probably offered Hire close to the minimum.
The imports you can get for the same money aren't much chop.
With a Strong Aussie core, keeping an import slot as insurance could be a smart move. If they lose Damo, Norton, Brandt, Kay, or even Wagstaff to an LTI, being able to bring in a hired gun would help.
In all honesty, that was probably the mistake they made last year.
I had previously advocated that they keep Hire as a TP, but again, that was their mistake last season. They kept Steindl around, used their 3rd slot on Crooke, and when Knight went down they were stuck with elevating Steindl.
I agree that this roster is top heavy, especially the bench, but that's how the Cats roll. They won a championship with Hire as the backup SG, so this is actually an improvement.