Fuck the environmentalists. Expanding where it currently is would be less damaging than constructing a new complex.
How do you know? If there is a hullabaloo surrounding it from that aspect and a proposed solution is to move it, I would assume it is likely that moving is in some way desirable from that perspective.
As far as the proposed move goes in general, it would be a shame historically I suppose but at the same time change is necessary in sport and traditionalists will get over it with time.