Yes it works.
And "fixing" it will be more trouble than it is worth.
Consider a few standard readied actions.
1. "I ready an action to charge the first enemy I see within my charge range."
2. "I ready an action to use Rain of blows when the warlord says "go.""
3. "I ready an action to use rain of blows after the warlord makes his attack."
All of these are pretty standard readied actions. (And if anyone who doesn't like #2, it can easily be reformulated into #3, with a little more table talk between players). In fact, any rule that does not allow #1 or #3 would be a bad rule since those are both readied actions that should certainly be allowed.
But, here's the catch. Either of those clearly allowable readied actions can be used to bypass certain conditions.
For instance, I am blinded, save ends. I ready an action to charge the first monster I see within charge range. At the end of my turn, I make a save. If I don't make it, I lose my action (unless the cleric, warlord or paladin gives me a save out of turn). If I do make it and I am now able to see an enemy within charge range, the ready goes off.
Likewise, I could ready an action to attack when the warlord says go or when the warlord attacks when I am blinded or slowed, save ends. The save would occur before the end of my turn, so, when the warlord says go (or attacks), there would be at least a 55% chance that I would be able to act, unimpeded by the condition.
Now, does this devalue conditions? Yes and no. Obviously, it is a way to sometimes get around debilitating conditions (blinded, immobilized, and weakened are probably the usual conditions to evade in this way). But it is not without risks. You trade your immediate reaction (which is more significant for some classes than for others), possibly your place in the initiative order, and a guaranteed action at a disadvantage for a good chance (depending upon how you word the ready--in some cases, you could avoid the chance of losing an action, but the specific readies that are under discussion do not accomplish that) of an action without a disadvantage. If you just acted normally, you would be guaranteed a useful (though not necessarily optimal) action--if worst comes to worst, you can second wind or full defense. (You would also have the option to use combat challenge, shield, etc as appropriate). If 45% of the time, you fail the save and get no action at all because your ready doesn't trigger, that is probably fairly balanced with having a suboptimal action that occurs 100% of the time.
Now, these are different readies than "I ready for when I am no longer immobilized"--which is arguably illegal since it doesn't trigger on an action from another character. On the other hand, it is possible to achieve similar effects with unquestionably legal readied actions (when the warlord attacks, for instance, which will always be after when you make your save), so there is not much point in standing on ceremony in this case. That is doubly true because it is easier to tweak the legal readied actions to avoid the risk of losing an action. (For instance, if you ready to attack a foe when you can see him and you fail the save against blindness, your ready doesn't go off. On the other hand, if you readied to attack when the warlord attacks (or says, "now!") your ready will go off whether or not you save, so it is all win).