Like I said previously, Victoria's biggest character flaw is being unable to see the bigger picture. She does the *right* thing in the moment, with no real thought to long-term consequences of what she's doing. Stopping a newly arrived and rookie trainer from going into the slums IS a logical thing and right thing to do. Its just that if she had succeeded the Tangrowth couldn't have been stopped, and Florinia was waiting for us to arrive regardless. Her attempting to prevent a wrong leads to a bigger one down the line. The situation with Kiki is the same. Victoria is doing the right thing in stopping us from fighting her...but at the cost of those we are supposed to be saving, which she just can't seem to see anymore.
That's the problem here. Its not that Victoria is a road-block per se, but rather how she's going about it. Fern also serves as a roadblock at some points, only he's doing it for selfish reasons, and hence is overall less annoying about it. Victoria is doing the same thing, but she's doing it for selfless reasons.