She's far from the weakest. Urgot still sits high and pretty on the worst win rate adc by a long shot and worst win rate champion with high frequency. He's routinely in high 30% to low 40% win rates.
MF is actually a lot more powerful right now. I wouldn't rule her as S tier adc, but she's probably at least comparable to Cait as an A tier adc, just different slightly in how she gets placed there. Her passive is incredible, allowing her to avoid a lot of engages by the enemy if she has a good read on them, and she can miss much less cs because of it, or roam more often. And her impure shots buff is amazing. Seriously, that damage racks up fast. Really fucking fast. And poor mobility champs can be defended with the right supports, like Morgana and Thresh, who are capable of saving their adc from bad positioning.
Achievement Unlocked: Solo Baron w/ Jungle Annie
And urgot is an underestimated champion, unless you're playing as an adc. I still have yet to comprehend why people consider him an adc, when he does much (MUCH) better as a solo laner.