TF2's CTF model is awful in general, really. Not being able to return intercepted flags (or at least making the return time MUCH shorter) and the Engineer being too good at defending unmoving objectives makes it way too stallish and one-sided. it would work as a 5cp map, probably. Just to faff about in like orange is. Or maybe a two-way 3cp map with two caps in the corners that oyu have to cap first before being able to cap the final point at the Ancients