I think it's just a natural progression, but I think there was a disappointing number of big companies getting involved both last and this year. I think the adoption rate will pick up at some point (hopefully) but it's been very slow in my opinion. I think there's much more smaller companies adopting bitcoin and those are just as important in my opinion so we shouldn't forget them.
It's probably too early to know if this year will be a good or bad one for merchant adoption but I'm curious to know why you think 2014 was a disappointing year for merchant adoption? Remember that no mainstream retailer was even remotely interested in accepting BTC before Overstock did so in January 2014 and since then about a dozen other large established companies have started accepting payments in BTC. Or are you referring to the fact that all of these companies currently use a service like BitPay and don't directly handle the coins themselves? That's understandably quite disappointing but I can definitely understand their reasons for doing so. After all, businesses have expenses to pay and 99% of the time these must be paid using fiat currencies.