Only draw the parts that NEED to be SVG in the SVG -- break it into the smaller subsections and then use markup and CSS to handle the rest.
Basically, don't slop it all into one SVG file and magically expect it to work. Same reasons one shouldn't use images as text, or try to create complex interactions between perfect size images and text content; it's all "not viable for web deployment" concepts.
Though IMHO, "not viable for web deployment" describes a LOT of what people are doing with SVG right now. It's cute for an icon or two, anything more is typically just telling users to go plow themselves.
ESPECIALLY if you're slopping it into the markup missing caching opportunities across pages.