I'd keep it, for a while at least, if you have the room for it.
As I mentioned, I've a Tricross, a Secteur and a hardtail and each has a different role. There are not many times I get to the shed and don't know which one I'm going to be riding as the journey and the purpose decides which is most suitable. Each one gets plenty of use and they all have fairly similar mileages under their tyres.
You will love the Tricross as the all-rounder that you were looking for. However, there will still be times, when the sky is blue and clear, the temperature is in the low-20s and the wind is negligible, that you will be very, very glad that you've got the Allez.