Hi,
I have already worked on similar project but using Rapsberry pi. Arduino + wifi shield is limited resource and the cost of hardware is more than Raspberry pi with peripherals. Apart from the cost factor, Arduino is having very limited processing + memory capability that will make the application involving networking like wi-fi very very limited. On the other hand, using raspberry pi, we will get 500% faster processor and huge memory and cheap peripherals.
As controlling over internet is not required, the raspberry pi can be the hub to host the server and a client can used used in desktop/laptop/smart phones to control the devices.
Thanks!