"Bandwidth is one, another is how much extra does it cost to design a facility to be more resistant to earthquakes as the vulcanization that offers those benefits of abundant geothermal power also means there is seismic instability."
While a perfectly legitimate concern, bandwidth is not a problem. Neither is the seismic activity. Any serious seismic activity is well mapped out and building for it hasn't been a problem since we crawled out of the caves (which admittedly was only around 1900). In my opinion, the earthquakes are outright fun, and we know well where the earthquake danger zones are. Start worrying if you hear that they want to build it around Selfoss. ;)
I'm born raised in Iceland but currently live in Canada and I've spent a year in Finland, and I can absolutely, positively guarantee you that the tech guru population per capita in Iceland is drastically higher than in either one of those. Even though the Finns are generally geeks... and I mean that in a good way obviously. Frankly, I think lack of geek skills in Iceland are not a problem for this particular project, and besides, the worst case scenario is that it won't be as monstrously huge as otherwise.
Of course I'm biased, I can only promise you that I'd tell you if I thought it were a problem.
I suppose the biggest problem would be the controversy over the energy it would require. Even though we are extremely lucky for how cheap electricity is in Iceland, there is also the counter-view that nature is to be preserved and therefore not exploited... even though it's the most nature-friendly way of producing electricity imaginable... okay, let's not get into politics. ;)
Honestly, I think that would be the biggest problem. Dealing with the politics.