The range restriction is pretty reasonable, maybe short is ok too. I don't think it requires extensive examination though, since the talent implies the Mechanic notices the flaw, seems like the examination is reflected in the hard difficulty.
We don't go with Short because we ruled that, even though the talent allows you to notice an existing flaw, you still need to take action - even if relatively minor and not something that appears to be obvious sabotage - to cause that discovered flaw to activate. We have overwritten the text that has the item just 'coincidentally fail' at the time of the character's choosing. The advantage of Bad Motivator in our game is that it allows for quick and covert sabotage (as opposed to the work you would normally do with Mechanics, not to mention the obviously destructive methods of blasters or explosives).