this is where most ppl go wrong. if you're going to sit there waiting for the next best thing every time, you'll never get something you truly want.
i bet a few months after the g3 gets released (depending on how much time it takes from announcement to release), i bet there will be new flagships with the new snapdragon, and you'll be in the same exact spot you are in now.
pick a phone you really like, because it works for you, not a phone because of the specs, or an android version and/or its potential updates.
best example? moto x. mid-teir specs, but an amazing phone to use.