I've been waiting for a Nexus tablet refresh for quite a while now... The 7 is getting dated even though the second gen is still quite a peppy performer. The 9 is limited to the same memory as the 7, and since i'm only using it in the airplane it's probably not going to be a real problem that it's only 32GB.
I got to play with an nVidia Shield the other day, and then went and did some research on it. It's about neck-and-neck with the Nexus 7 for most features i'd care about, *plus* it's got a stylus... Being an old Palm guy I have been missing my stylus for ages... I'd buy one, but the design is a year old and nVidia is apparently refreshing it in the fall, so i'll wait.
There are no plans for a Nexus tablet refresh this year, according to all but one available report. The only indication of a Google tablet coming this year is from a report back in spring that Google was working on a dual-OS Chrome/Android tablet. My laptop is a Chrome laptop, and has served me phenomenally well for two years. I bought it on a whim, and it's honestly been the best computer i've owned for ages. Not practical in a cockpit though, so i'm still looking for the "perfect" tablet.