It's doable right now, and I'm a fighter who spends most of the time in 25% hp (around 300-400hp) because of overload using only knuckles. It's just not effective to farm it while you are alone because
- Having more people in a party increases your drop rate
- It's just not fast enough
The real question might be: "If I'm not good at the game right now, will it be possible to solo ultimate quest if I get overgeared/overleveled?"