iOS 7

I'd argue most of my beef with the armchair commentators is they are making what appear to be deep criticisms of iOS 7 without having actually used it, and without taking into account the fact that it's beta 1. They are shipping a new "letterpress" text treatment in UIKit, my guess is that they will apply this treatment to text if it is sitting on top of a similar-colored background, but probably have not worked out the details yet. I could see it being a reasonable technical and design challenge since you may need to apply a treatment to only part of a glyph. I'd ask the poster what their "duh, so obvious" solution is to their "duh, so obvious" observation. (Note: "leave the status bar alone" is not a valid answer here, since the design goal is to have the content in iOS 7 take up the entire screen. If you have a problem with that decision, argue that point, but realize it has nothing to do with status bars anymore. Even if Apple left this pretty glaring flaw in their design, they may have decided to do so because having content take up the entire screen is worth this cost, and the onus is on the critic to explain why it is not worth it, not that they are too stupid to have noticed this edge case.)

Basically if you see something and it's something that 99% of developers would identify as a potential edge case, you can be sure Apple considered it too and at least made an explicit design decision to deal with it or punt for later betas. If they made an explicit design decision, which is assumed, then you should try to understand that decision and then critique that decision and its tradeoffs beyond Comic-Book-Guy-esque "this is so obvious they are so dumb how could they miss my clever edge case I've discovered." Let's say Apple really do see that white on white is an issue, and actually decided to leave it that way and ignore the case altogether. Why would they do this? At least address this question if you are going to critique the design. The OP assumes it was an oversight, not a design decision or technical debt, which is kind of insulting to Apple designers and engineers.

I would prefer if before starting a complaint about text legibility, colors, contrast, and so on, if people would include a disclaimer of if they have actually based their opinions upon viewing the design on an actual device.

First off, I don't think they are explicitly trying to fade out older messages. The received message bubbles are gray and don't seem to have a gradient effect going on; it's only the sent ones which are colored (green or blue) and have the gradient. So I think Apple's goal here really was just a gimmicky gradient effect for the colored (sent) messages.

More evidence for that is that the bubbles themselves don't seem to change colors as you scroll; rather they are just sort of a mask for an underlying gradient layer underneath (so you can have one large bubble which fills the screen and is light on top and dark on the bottom).

But even if their intention was to make older messages fade out, it was still severely misguided. It is trivial to discern which messages are older (they are higher in the chain and therefore further from the text input for a new message). Users of iOS have been familiar with this for years (and isn't the new UI supposed to move away from explicit visual cues since the assumption is people are used to it by now?).

Moreover, it actually hurts usability, since users now have to scroll more often to get messages in the readable portion of the screen if they want to read through a conversation.

And, on top of all that, if there is only one sent message in the conversation, there is actually no way to bring it into the readable portion of the screen due to the snap-back! (Further evidence that this was intended to be no more than a visual gimmick.)