It's akin to weak measurement - we can measure which slit the particle goes through without disturbing the interference pattern.

http://en.wikipedia.org/wiki/Weak_measurement

I'm not seeing how that is so. You can measure every aspect of the oil drop at every point along the path it takes, before and after and as is passes through the slits and it won't do a darn thing to the pilot wave and the interference pattern. The ability to measure is 100% classical 100% of the time.

We can measure every aspect of the oil droplet because we're measuring it with trillions upon trillions of infinitely smaller and faster photons which give us a great insight without disturbing the structure. What would we bounce off of photons to get an equally accurate picture without disturbing them?

The analogy isn't a problem. The fact that there's nothing small enough to observe photons like we can observe the oil is a problem, but it says nothing about the integrity of the analogy.

In the analogy the water is space-time, meaning "observing" the droplet like we observe photons would require shooting another droplet past or into the first droplet.

I agree with your first two paragraphs. But, be careful about the last. The pilot wave in Bohmian mechanics is not a wave in space time, but rather a separate physical entity. Basically the dynamics of both the particle and its pilot wave are described by different portions of the wavefunction. (The wavefunction is complex, and so has enough variables to describe two physical quantities).