If the check is unseccessful, the spell is not learned and another may be taken in its place. The unseccessfull spell may be attempted again at the next level.
That's a good language revision.
As to what I want...
Originally, I wanted players to make (or at least, have the option of making) their own spells. Unfortunately, like I said, I couldn't find an already published version of spell design rules that had the flexibility I wanted and that I believed my players would have liked. Or tolerated.
The system I was designing had all of the flexibility, but the detail was such that it amounted to learning a new game...I knew I couldn't sell it to the players.
This system, simple though it is, gives me much of what I want. The researching PCs will (at least) be able to learn spells that don't appear in print anywhere in the world, meaning a crafty player could concievably take a combo of feats and spells that really optimize their PCs. Imagine a PC who memorized a variety of Magic Missile spells...some Admixed, some maximized, some with extra range-
I'm also considering working in elements of the other system, so that spells could really get customized. I could see someone designing a "Sundering Arrow" or "Explosive Arrow" once I figure out what kind of LA to assign.
ARGH! Something else I left out: Regardless of the modifications to a spell, you can still apply Metamagical feats to it, even the same one as was used in designing the spell. The exception is Opposed School spells- once learned, they may not be metamagically modified, even by items that would allow you to apply a metamagical feat to a spell.
Now, if they don't learn the spell they get to learn a different one. This will probably not decrease the attempts to learn non-PHB spells, but it will significantly decrease the number on non-PHB spells actually learned
I don't know- crafty players will prioritze the non-PHB spells they want to learn so they're the first attempts, playing the odds and hoping one of them will get learned. After going through all of those, they'll pick up the non-PHB spells.
Heck- the rule is even potentially abusable if I have enough researcher in the party. This rule only affects the spells you're getting as a level benefit, not spells that are already written down somewhere. With 2 researchers in the party, the smart guy goes for the tough-to-learn spells, while the lesser student learns the easy ones. Then they compare notes & trade spells.