If you just want to "view" images on the field, and don't want to carry a lot of gears, an EyeFi card and a portable tablet such as iPad mini 2 would do. iPad mini 2 is more portable than iPad Air, but the iPad Air's bigger screen is a bonus. Since I own both iPads, I would say that colour gamut wouldn't be an issue while shooting on the field. In other words, most people wouldn't notice the minor colour gamut issue on iPad mini 2, unless you have iPad Air and iPad mini 2 side by side.
If you want to tether on the field, a laptop would do a better job.
_________________AntBlog701 | SillyDog701
Apple: MacBook Air (11-in, 1.8GHz i7), Mac Pro (12-core 2.66GHz), MacBook Pro (15-in), iMac (21.5-in, Core i5), Mac mini Server (2.66GHz), iMac (24-in, C2D), PowerBook G4 (12-in, 1.33GHz), iMac G4 (1.25GHz)x2, PowerMac G4 (dual 1.44GHz).
iPhone: 5s, 5, 4S, 4, 3G
iPad: Air, Mini, 4, 3, 2, original (all models are 3G/LTE)
iPod touch: 5th gen x2, 4th gen x2 & 1st gen,
4 x AirPort Extreme, 2 x Time Capsule...