Well, apart from this article sounding quite a lot like an advert, I can see a number of problems with this.
Weight, as has been mentioned above, most current buildings won't be able to take the weight of this type of oil bath. Ground floor, mmm... maybe, with a good thick concrete pad. . First / higher floors, no way. Greenfield sites would be able to build the necessary infrastructure, but the cost might put a been counter off. Also the infrastructure required to manage the oil and it's subsequent water / air cooling will be complex, Involving skills not yet normal in a data centre. The weight of an oil filled server is going to be a problem too. (Yes, I know that servers can drain, but you have to raise it out of the oil bath to allow that.)
Contamination, muck and debris from the blades & components themselves would be an unwelcome intruder into an oil baths circulation system. Replenishing / replacing oil is not usually a clean job.
Repairs & replacements are going to be a nightmare. Taking any server or Blade rack out of the oil bath is going to very messy. It is also going to take much more room to operate on the oil bath(s) than that of a current air cooled rack space. Another cause for oil replacement, And what about the units warranty when returning a (new-ish) component for replacement? Upgrading, well just forget about that. Replace the whole bath with a new unit.
Fire risks. Now have a quick word with your insurers as to how you're going to minimise the fire risk and how much they'll want to even consider insuring you. Oil burns, electronic components get hot, sometimes very hot. Should the temperature of your oil bath exceed a safe limit the whole bath has to be taken down. How many servers did you put in there?
Leaks, they're going to be fun. They will happen, usually when most inconvenient. Just what are the health & safety implications of a large number of litres of oil washing round the floor going to be?
Currently oil baths are fine for one offs, or trial installations, but the technology needs to mature a lot more before it becomes viable for large data centres.