In my numerous basic motions practice, is it common for people to bend and straighten the right arm without enough "forward"
I hit shots much better focusing on the right elbow finishing opposite my left hip, much more "compression" of the ball
Would this "not enough forward" be one way of running out of right arm?
That's a great discovery moment. It's a very common problem as you suspect. The Right Forearm is brought into Impact On-Plane so your Right Elbow should continue Forward as you've discovered.
When the Elbow quits, it also leads to a Bent Left Wrist, disrupts Hinging and gives control of the Clubface to the Right Hand, destroys the Wedges, no #3 Accumulator Roll, etc.
Though the Clubshaft is in the cup of your Left Hand during Basic Motion, I still think that you should see the Clubface Rolled at the end of the Stroke (Swingers). This should occur by Rolling the Wedges and not simply by Rolling the Left Wrist. So, is your Right Elbow at least Level with your Left Elbow at the End of the Stroke and not below as it was at the Start of your Downstroke? It's only my opinion.
Yes, the bent right arm at impact means there is something left in terms of thrust through the impact interval. Compression resulting. Like a boxers punch the arm is bent at impact and then straightens.
Assuming one accumulator Basic Motion. The Swingers Right Shoulder takes the bent and passive right elbow downplane. The Hitter on the other hand, who actively straightens his right arm, zeroes out his pivot (to prevent having two accumulators powering) and therefor needs to pre position his Right Shoulder in a suitable position that allows for the right arm to straighten accordingly.
A good way to find this right shoulder position is to go to your desired both arms straight , Follow Through, Finish (Station 3) position and freeze your right shoulder there before going back to Address (Station 1). (Station 2 being Top in the Address , Top, Finish, Three Station triad.)
So your left hip notion might be good for some Finish positions but not all.
Hope this adds a little more precision to your discovery.
PS If you havent already purchased it the three disc Alignment Golf DVD discusses this and much much more in great detail.