I will go so far as to say that this is a decline by degrees. The new railing is charmless and visually distracting compared to the charm and simplicity of the white wooden handrailing. The increased height of the bridge railing is completely unnecessary; it is even taller than the surrounding green fence for the planters. I can't fathom that kids managed to fall into the waterway below.
If the wood was rotting, then the handrails could have simply been replaced. That's exactly what happened to the smaller, more curved wood bridge just across the way when it was deteriorating a few months ago; why couldn't this bridge get the same treatment?
It's a sad change. I'm not sure exactly how long the Carnation Plaza entry bridge has been around, but it sat unchanged from its original form for at least 50 years. Yesterland has a picture of it from the 1950s in one of their "Then and Now" photo series:
What I love about this picture is that you can see that the railing of the bridge once matched the wood fencing that surrounded it. It shows the original context of those isosceles and right triangles formed by the old bridge. It's a familiar, understated country feel.
Here's a Davelandweb photo of the bridge, dated February 1960. It gives you a sense of the height of the old railing - tall enough for Daddy to sit on, but not short enough for the kids to inadvertently fall off or through.
I think this bridge, given its close proximity to the center of Disneyland, deserved some attention. It's no castle drawbridge, but it lived through half a century of Disneyland history virtually unchanged, even as Partner Statues, path widening and all sorts of other cosmetic and logistical changes were made nearby over the decades - until now. Now, it's still a bridge, but one that tries too hard to prevent guest stupidity.
It's hard to explain what charm looks like, but even understated charm is missed once it's gone.