That sound strange - most of the Savannah rooms face Arusha, and the deluxes are only the upper floors (they're slightly larger and include a daybed). They may have changed policies, but it might be worth calling again and asking. The first cm may have given you bad information.
At any rate, we've always had rooms on the Uzima Savannah and really prefer it. You don't get the zebra or ostriches, but you do get a great variety, and they tend to cluster closer to the balconies. On the maps, Arusha looks broad and open, but it has a lot of places for the animals to hide, or some corners they tend to not go into in clusters - just 1-2 at a time. The Arusha overlook also cuts the savannah in half, blocking your view. You might get good views if you are at the very end of the trails looking in, but that's quite a hike from the lobby.
You'll see giraffe on all savannahs, and they are good at getting the animals to move about - it's just that some areas are better than others. I think any savannah view room will be highly rewarding.
CMs at the desk have told me that they think room numbers x456 - 486 facing the Uzima savannah have the best views, which is what we've had. This is the pod off of Zebra trail where one side faces pool, the other side faces Uzima. That hall is great - steps away from pool and Mara, it's own elevator, and laundry on first floor next to elevator.
Dirk