458 polys actually sounds a little low, especially for an entire environment.  I wouldn't worry about cutting geometry until you get into the thousands.  In fact, you may be providing an item that's under detailed.  Sometimes, items that don't have enough segments in them can render wonky, because they depend almost entirely on shader smoothing to make them smooth.  This can cause strange surface shading, or self-shadowing.  For hard surface objects, geometry which is too low res can cause "light leaking" and issues with GI in some physical render engines.  Also, if the objects are hard surface, and they aren't provided enough geo in critical areas, then your objects begin to look fake, because they  contain edges which are way too sharp, or corners that are unrealistically perfect.  Just be sure you're adding bevelling and rounding corners on objects to catch light.  There's nothing wrong with low poly, if it's done right.  Many times, people will model in high subdivisions, only to use that high res version in a low res retopology version, where all the edge detail and stuff are baked into high detailed maps.  If you're not using texture baking, then you wanna model in some detail.

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Tools :  3dsmax 2015, Daz Studio 4.6, PoserPro 2012, Blender v2.74

System: Pentium QuadCore i7, under Win 8, GeForce GTX 780 / 2GB GPU.