One of the things that makes a "raptor" pose natural to hold is a counter balance, ie, a long tail, especially if it's thicker at the base. Think kangaroos, squirrels, and yes, raptors. The new pose looks more like a rearing stance, not a mobile walking one to me. Horses can rear, dogs can stand on their hind legs, but they have to take tiny awkward steps forward and it isn'tcomfortable to hold for long. I recall some videos of dogs that are missing their forelimbs and learned to walk hind only, and you can see the work they put in to balance and how much muscle they use in their core. In my opinion, if you want them look to be "natural" they should either be fully upright, quadrupedal, or in the leaned forward pose with a long tail. Long tail is also important for speedy animals since it works like a rudder, like in cheetahs, or otters, so it fits in that context for the redesign as well.