That's the major hurdle. The other is the coarse rankness of the material, where women--it's always women--are killed serially, covered in animal fat to immediately preserve their scent, then the fat is scraped off and reduced down to its basic (one would presume) pheromone, and collected as an eau de copse. The plot all comes down to a...boil...when Alan Rickman's protective father suspects his daughter is being stalked by the little stinker, and highs her to the hinterlands at full gallop. Despite his precautions Grenouille is able to track them on-foot despite the dughter's intoxicating scent being mixed with that of a sweating horse. This is where Tykwer's inability to sell the scent works to his advantage. You're not supposed to think about that in the absence of evidence.
There are other troubling aspects to it, but let's come right to the nitty of the gritty. "Perfume" is just another in a series of serial killer movies which (sorry) boils down women to objects with an aspect to be coveted and destroyed for. It's not unlike "House of Wax" (whichever version) or the skin-suits of "The Silence of the Lambs." Despite being gussied up with period detail, sophistication of technique and aspects of subject matter, "Perfume: The Story of a Murderer" is just another horror movie with pretensions of grandeur. Despite all the attempts to cover it up, you can't hide the basic stink.