Pacific Park is small but there are ways to do this without expanding the pier's footprint or sacrificing parking spots.
The easy answer is remove the iconic Trapeze School... but I think they've been resistant.
The hard answer is to start expanding on top of buildings Gröna Lund style, which would mean significant rebuilds of the rooftops to accommodate attractions. It's more of a long term investment really but also a decision point as to whether they actually want a larger amusement park moving forwards. Right now between their price points and attendance they're sustainable with exactly what they currently have, every so often something gets changed out for updated hardware to move with the times but a park like this can stay in a holding pattern.
Obviously a second significant coaster would shake up their budgets and operations a little, but it's cool that they're actually considering it. If they decided to take advantage of those rooftops and start fitting in more rides it would go from a small to medium sized amusement park.