The fabled British team has struggled for success since Jacques Villeneuve won the last title in 1997.
Not only that, Brazilian Pizzonia said he has heard that Williams is investing heavily in other, less high-profile areas of personnel.
"What has surprised me most, knowing Frank Williams, is that he has invested a lot on the technical side of the team," he explained.
"They are hiring new people, significant people, which is financially not cheap for the team, and if you analyse the history of the team, they haven't done it much before.
"They have always sought to promote young people in their own factory who could have a bright future, but I think now we could see a very strong improvement," added Pizzonia.
He said Williams' decline dates back to his own time at the time, some 10 years ago.
"There were relationship problems with BMW, the team was losing competent people and then there was the financial side with the loss of strong sponsors and from there the situation got worse.
"In recent years they even had to go down a path they'd never gone down before, which was to have paying drivers.
"But I hope now we see a turnaround and the team goes back up again," said Pizzonia.
He also commented on F1 more generally, including the recent complaints of some active drivers who are unhappy with the sport's reduced speed due to the new engine and aerodynamic regulations.
"There's two sides (to that)," said Pizzonia.
"For the young drivers it will be much easier to adapt, because the leap from GP2 and the World Series is much smaller.
"But I think there is some frustration for some drivers who see that formula one is going backwards in terms of speed. But I understand that F1 is doing it for safety and for a range of other factors.
"As a spectator though I have to say I am not really in favour, because even on TV the speed reduction is apparent. It's not as cool as it used to be," said Pizzonia.