XFCE apparently works in dCore but i've never heard of anyone using it and it may not behave the same way compared to a full featured Linux distribution (Control Panel items, etc). Maybe a dCore user in the know will respond. From my experience, once used to a lighter weight and more flexible Window Manager never want to run a full Desktop Environment again. Misalf's suggested Openbox is great, my current favourite is Fluxbox which has a built-in panel. JWM and IceWM appear stark but resemble a more traditional XFCE type layout. All of these WMs are extremely configurable, can be made to look and perform amazing.