Draco - reread the OP. At this point I think we're all agreed on what it should be. But your invocation of RAW is incorrect, and/or your interpretation of the problem scenario is.
Readying an action based on a legitimate trigger (movement, say) that occurs during the turn of someone who falls before you in the initiative order will always trigger the problem, by RAW, with certain exceptions (like if you're last and they're first, or if others also juggle the order in the meanwhile). The whole problem is that when you take the triggered action it resets your initiative from a spot in the initiative order that's yet to come (your old spot in the order) to one that's already gone by (by definition), and does so (by clear and unambiguous RAW) without any of the compensating factors covered under Delay Turn.
Nebulous - you're right that this would fix many of the issues right there. But since it's not a comprehensive fix, my personal preference is to address the underlying issue (which I've done), and then not add additional constraints for players to have to remember regarding Action Points... which, in my experience, are being used much more often than Ready Action.
(Edit: Walter, yes. Correct on every count. Including your additional note at the end. I'm going to wait and see if this becomes an issue, though. There are fixes which could be possible to it, but they're not as intuitive, so I think I may just discourage this behaviour OOC if it comes up, and trust my players and DM to be reasonable about it. It's not one that'll happen by accident much, I think.)
As for anyone who wants to contend that we're seeing more loopholes crop up as a result of the fix, I can only assume that they're just not paying attention. The current fix, which was proposed in the OP and has not changed a whit, remains airtight. I'm quite honestly puzzled by why people keep suggesting alternate fixes which, frankly, aren't.
It's just a clarification to the "your initiative moves to spot X" part of the Ready Action rule. How do you move your initiative token - do you just slide it without doing anything else? The answer is no. You do it by using Delay Turn on it, when it comes up, to slide it into the new position. That way you get all the rule precautions built into Delay and everything happens when it should. This is NOT complicated. It's just also not in there, right now, and thus is indeed a fix.
(And, as I think we've shown here, it's also not 100% intuitive, despite any assertions to the contrary. Once I showed people where the problem lay, at least half of the proposed fixes have been either incomplete or far more loophole-ridden than RAW. And these are the fixes which these people would have applied at the gaming table, if a player brought it up. Even among those proposing versions of the "just use the same rules that are under delay turn", there's confusion on when to insert these effects from Delay, and an overall lack of clarity which I know would fubar many of my players if it came up.)
My solution appears to be airtight. It also appears to be equivalent to, if more precisely stated than, the proposals offered by chaotix42, DracoSuave, and (sarcasm tantamount to hostility aside) ricardo440. If some of these people want to suggest that the fix is completely obvious, I have no stomach to argue that; all I can do is point to this thread and shrug.
As far as I'm concerned, this thread is closed. That's not hostile or defensive, that's just an old forum habit - I asked a question and raised a point, and my question has been answered to my satisfaction and the point brought to folks' attention. If, by now, people still either (a) disagree that there's a problem, or (b) think that some other fix would be sufficient, well, power to you. I will still keep half an eye on this thread, though, and will happily answer anyone who either (c) is still confused about the problem and its fix and honestly just wants clarification, or (d) spots a loophole which is not caught (or is caused) by the fix.
The bit about sustained effects I will fork to another thread for clarity.