Saying Jake Williams is bad because Dr. Milan Christopher exists seems incredibly unfair given the fact that Milan is basically the best Ally in the game. Even taking taboo out of the equation, Jake is still incredibly good with Milan in your deck even before grabbing Charisma. For one thing he can help you draw into your other Seeker allies (Milan, Rook, Horowitz). Revealing and putting locations into play is very easy thanks to Pathfinder and Shortcut. His soak and his AoO prevention is also HUGE for Ursula decks that aim to clean up a scenario quickly. It lets Ursula rely on her 4 more strongly, as she doesn't have to worry about losing as much tempo if the board gets cluttered. This is especially nice in true solo where one of the biggest issues a true solo deck can run into is being bogged down by too many enemies at once. Jake, alongside Ursula's free action, makes that so much less of a concern. Jake is incredibly good, and alongside the run of great Seeker allies Ursula can run makes Calling in Favors a very strong choice in Ursula decks.
In a game with lots of players, Jake's reaction ability becomes less consequential, but in a 2 player game, drawing an extra card nearly every turn and ignoring an AoO becomes extremely valuable. In some scenarios where there are location encounter cards, he's just nuts. He's definitely undervalued!
Overall probably the worst thing about Ursula downs is her special card. The bonus this cards is nearly non existent because you move and the enemy is still on you at your new location. Maybe helps get enemies closer to allys so they can fight sooner. Jake is a good damage soak though at 3/2. Overall id say hs is easily replaced by dr. Milan. However if you have him out before you get one let him tank a few hits first.