Mas being this strong at the end of week 1 is more the wildcard than anything else because of his mostly having Carlos Sastre'd, Steven Kruijswijked or Ryder Hesjedaled his way to success thus far in his still-developing career, getting better as the race goes on and therefore normally spending most of the first half of the race managing losses and jockeying for position to progress from as his form improves. Here him being in such an advantageous position and riding so well at this point in the race could be ominous for the opposition.
As for the field, of course this isn't a weak field. But you can sometimes get fields that look a lot stronger on paper than they turn out to be, and this will likely turn out to be one of them, depending on how the overall picture looks at the end. A race where underperforming elite names fill out the lower end of the top 10 is likely to be more fondly remembered than if they DNF or drop out of the top 10 and that gets filled with one-and-done contenders, secondary riders and so on. Remember, in 2011 Igor Antón came in as a favourite, having crashed out of the lead the previous year, Joaquím Rodríguez, Vincenzo Nibali and Michele Scarponi were all there but underperformed, and Klöden and Zubeldia were also starting for RadioShack. Lots of people who would later go on to be reasonably good GC riders like Talansky, Martin, Poels, Majka, Kruijswijk and Fränk were there too, but if you look at the top 10 you say it's a real weak field. Remember we've already lost Valverde and Carthy, two strong riders indeed and who would have been targeting the event. Landa is Antóning his chance to lead, Carapaz is running out of gas after a very busy season which is obviously already a very enviable one regardless, he can be forgiven a washout of a Vuelta. Of course it's a shame we don't get the Dauphiné version of Padun or a non-crashed, non-delayed Romain Bardet, but there's always people who underperform expectations for a variety of reasons, illness, injury, crashes mid-race, tactical errors that lead to a change in focus, over-training or poor form management, it happens. I mean, hell, you could look at the top 10 of this year's Tour and say that it was a letdown of a race because a lot of the biggest pre-race names weren't achieving to their level, with Rogla crashing out, Ineos' much-vaunted manifold leadership being derailed very early leaving them with all their eggs in the Carapaz basket, ISN having a bunch of riders with GT performances but none competitive there, and established names like Quintana, Nibali and Supermán being derailed and soldiering on long after their race had fallen apart. But nevertheless, it wasn't a poor startlist, and neither is this one.