The core problem with Twitch jungl isn't even his clear, or the fact that if you get invaded by anything more aggressive than a Janna, you're gonna die; it's that as a hypercarry ADC, he needs a huge amount of gold to be useful, and the jungle just doesn't offer that kind of cash. Unlike bruiser/bully ADCs like Graves or Quinn, who can lean on their base values to remain relevant even with the lower gold income, Twitch is entirely dependent on his autoattacks.
Even if he was somehow changed to be less-gold reliant (increased values on E, better damage to minions and monsters from passive, higher AD from ult), he would have to have a lot of power removed from his Q in order to not be strictly better than Evelynn, at which point lane Twitch is essentially an immobile version of Kalista.
tl;dr
Twitch could be made into a jungler, but doing so would require such a drastic reallocation of his strengths that he wouldn't really be Twitch anymore.