Your 1) is putting a somewhat rosy face on the academic failure scenario. In reality he doesn't just drop out and walk quietly away. More likely there is some period where the academics become an issue, possibly a midseason suspension, friction with the coaching staff etc. Given the attention his recuitment/signing/admission has already received there is then a new flood of negative press from the likes of the freep as well as the MSM.
Not saying this will happen but you asked for the scenario under which we are better off for not admitting him in the first place. This is it and it is one that should be avoided at all costs.
Not saying any of it is right - just the way it is.