The Bell mania is reminiscent of the Jahvid Best mania from a few years ago.
A lot of hubbub made over a week one with a couple extremely flukey touchdowns, when the rest of his production is pretty blah, if not out-and-out useless.
Forced into any kind of full time role, Bell would find himself on the outs in a hurry. As a backup to Bush, he's going to see flukey results like he did in week one about once per decade, because he's no kind of goalline back. He was in for short TD's because of timing and natural rotational issues, not because he was a better bet to punch it in.
Owners who didn't sell EXTREMELY high on this guy within half an hour of his 2 TD performance are going to be kicking themselves all year. They might get a brief reprieve in the off chance Bush suffers a serious injury and Bell has to take over. But the relief would only last until they saw how incapable he'd be if he had to carry a full-time workload. I suspect the Lions would be in panic-and-committee mode in less than a week.
Bell's just not a legit front line NFL performer, and shouldn't be regarded as such. Dwindling returns imminent.