Tubercles on Drive fins? IMO, I would have to say not realistically beneficial. What I see is several factual statements that aren't necessarily relevant to the Mirage Drive application.
1. Whales get their speed from the fluke or tail fin, not the pectoral fins. We don't find tubercles on flukes.
2. A Mirage Drive fin develops thrust much like a fluke, essentially a variable pitch, reversible prop.
3. Tubercles are found on the pectoral fins of Humpback whales (not a particularly fast whale). The Humpback has unusual acrobatic and maneuvering abilities for its size though, attributed largely to those long pectoral fins and the leading edge tubercles. The shorter, cleaner pec. fins found on other whales are far more aerodynamic.
4. Since tubercles pertain more to lift and drag than speed, the better potential application might be with the rudder if we want more directional control.
So what about Whalepower windmill blades? If you read the details, they never did a direct comparison with an identical "tubercle-less" or any other prop -- they just read the power specs off the plate. Neither did they get around to calibrating the test instruments. Small details. That isn't to say that the concept is bad, but the result wasn't as conclusive as it appeared to be.
The VG tape on helicopter rotors? This leading edge treatment might theoretically improve Turbofin efficiency, but any positive effect, considering our fin construction and operating speed would doubtfully be significant, compared with adjusting the clew setting for optimum AOA (angle of attack). Getting the tape to stick to a flexible fin surface is another matter.
Matt Miller's mention of sanding the hull on sail boats -- I believe that was with 400 grit sandpaper to insure smoothness and a laminar boundary layer over the hull (opposite result, different application from the tubercle concept).
Time will tell if tubercles offer anything new or are just another variation on well established existing applications such as slots, slats, boundary layer devices fences and winglets. I'm not holding my breath.
Great video on the whales though! 
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It's cheaper that way.
