McLaren announced in the morning that Frenchman Eric Boullier, the former Lotus team principal, would start work on Monday in the new role of Racing Director - effectively running the team at grand prix weekends.
Former principal Ron Dennis has also wrested overall control of the team back from Martin Whitmarsh, whose future is uncertain but almost certainly lies elsewhere.
Button, the 2009 champion now in his fifth year at McLaren, welcomed Boullier's appointment.
"I think it's good to have fresh ideas," he said.
"I think he does add to the team. The team will never be changed by one individual, but I think he does add something and I think when the management structure is complete we will be in good shape."
McLaren suffered their worst season since 1980 last year, failing to appear on the podium with Button's fourth place in Brazil their 'highlight' result.
The former champions knew they were in trouble from the very first test but Wednesday's evidence, with Button top of the timesheets and the rumour mill talking of them having a 'secret weapon' with an innovative rear suspension design, was more promising.
"There's no horrible issues with the car itself, no big issues with the power unit, in terms of how it delivers, so the basic car itself is where we want it to be," Button told reporters.
"Our first day last year was quick but the car had its flaws and we could see that on day one. The car was bouncing around a lot and we had our issues which were not going to be easy to solve. This time we don't have those issues."
Formula One has a new V6 turbo engine with energy recovery systems now, replacing the screaming V8s, and Button said that although the noise did not sound as good, he was enjoying driving the car.
He was also encouraged by the team's ability to resolve problems quickly.
"We had a lot of issues yesterday and it's nice to see that we were able to solve them overnight. Not a lot of laps today, 43, but it's been a positive start," said the Briton, the most experienced driver in Formula One.
"We did lots of different runs today. We weren't able to do any long runs because we had a few little issues but the good thing was that we were able to solve them quickly and get out there and put some laps in."
If Button appeared subdued, despite his comparatively upbeat assessment, it was entirely understandable given the sudden death of his father John - a constant travelling companion - earlier in the month.
The driver wore helmet depicting the cartoon character 'Papa Smurf' - the nickname Button gave to his father - with 'RIP Papa' on it.
A fitness fanatic, and regular triathlete, Button was also chafing from a knee infection that he said had prevented him from training for three weeks.
"I did a hell of a lot of training over the winter in terms of diet, really limiting my intake, but in a safe way," he explained. "But that's all gone out of the window in January.
"And when you are sat on your arse all day like yesterday, you want to eat, so it's not been the easiest. I'm not as light as I will be at the first race, but I'm definitely going to lose another kilo by race one."
- Sports & Recreation
- Motor Racing