Confession or clarification or ...
My post about the importance of a straight lead arm as the secret of good golf was just a little off target - I confess - it needs clarification.
The lead arm at the top of the backswing should, if possible, be extended. No doubt about it - maximising the size of the swing arc is beneficial. But going 'straight' - that's another story.
There are plenty of less flexible, somewhat weaker, and perhaps older golfers who need a decent length backswing to generate clubhead speed - which can't be achieved with a dead straight lead arm and a really short backswing. Of course, a hyper-bent arm is the sign of a hacker. That's not conducive to decent golf.
I said previously that a bent arm in the backswing means that timing becomes more difficult. But having thought about it, timing, achieved through good tempo or rhythm, is not beyond the average golfer. It's just that good rhythm isn't something that many average golfers think much about, let alone strive for, let alone achieve.
Many of us do, however, marvel at the ease with which top golfers (on TV mostly) swing the club (all the way through the bag). And these same golfers will tell you, if you ask, just how important their rhythm or tempo is in hitting the ball well. This good rhythm is inimical to good timing. It also maximises swing speed for swing effort.
The danger with any swing thought is that it can be overdone. I like the logic of maintaining a straight lead arm in the backswing to help with consistent ball striking, but I know that if I overdo it (the thinking about it) I am very likely to lose my timing.
I now have to confess that I'm coming to the view that it is more important to focus on rhythm and timing in one's golf swing. If this focus allows or encourages the lead arm to straighten nicely in the backswing, excellent. But like many things in golf, it's advisable to identify what is cause and what is effect. Clearly I am a slow learner; because I have failed to make this distinction more than once.