SANTA CLARA — The 49ers have given the opening year of Levi’s Stadium about a “B” grade. But from the turf that kept being replaced to the ongoing traffic woes to the sterile atmosphere that didn’t seem to provide much of a home-field advantage, many 49ers fans were less impressed with the team’s first year in Silicon Valley.

This newspaper stayed in touch with several dozen season-ticket holders and other fans throughout the year to gauge their experience, and nearly all of their grades ranged from a “C-” to a “B,” with a few failing grades sprinkled in. The consensus was that the Santa Clara stadium was an overall upgrade over aging Candlestick Park — and improved as the year went on — but it wasn’t always worth the sky-high cost of admission.

The $1.3 billion sports palace opened last summer with the team predicting it would set a new standard for NFL venues — and in some ways, such as environmental and technology features, it has. But there has been no shortage of flaws that emerged from the opening year, which concluded with a college football bowl game Tuesday after the last Niners game two days prior. Among the other issues were the overwhelming heat, a strict new code of fan conduct and the sparse crowds during non-NFL events.

The Niners say they are proud of the stadium’s inaugural year — aside from the team’s mediocre performance on the field — but realize it needs to get better, and are already working on improvements for next season, which ends with the stadium hosting Super Bowl 50.

“I certainly appreciate (fans’) patience because there’s no question at the beginning part of the year we had a few hiccups and a few things to improve on,” said Al Guido, the 49ers chief operating officer. He graded the stadium’s first year “a B or a B-,” echoing the “B” grade issued a month prior from owner Jed York.

The Niners had to contend with exceedingly high expectations that came with years of hype, and even higher prices. Seat licenses cost $2,000 to $80,000, while tickets were about double the price of Candlestick, with a family of four paying $642 for tickets, parking and concessions, the most in the NFL, according to the independent Team Marketing Report survey. By the end of the year, there were no shortage of fans selling their seat licenses for below face value, while most single-game tickets were also being sold at a loss, although the Niners had dropped out of playoff contention by then.

Perhaps the most commonly cited complaint at Levi’s this year was the lack of any loud, unique atmosphere that has lifted teams at Candlestick, AT&T Park and Oracle Arena — a key ingredient that keeps fans coming to games when their TV and couch provide a better and much cheaper view. As longtime Niners fan Mike Sanchez of Hayward put it, “there’s no magic.”

“It’s a very sterile stadium,” echoed Max Krieg, a 49ers season ticket holder since 2006. “It lacks all that AT&T Park has — culture, diversity and character.”

The stadium’s most-lauded features — the suites, fast WiFi and playgrounds such as a fantasy football lounge — also served to distract fans from the action on the field. The effects were most clear in the plush, deep-red seats at midfield, where 9,000 fans paid at least $20,000 per seat license and received access to the swanky, roped-off clubs inside the stadium. Those party zones were so popular that the actual club seats in the stands were largely empty, leaving a huge red hole of empty midfield seats that was hard to miss on TV and routinely mocked on social media, draining crowd noise pivotal to an NFL team’s home-field advantage.

“There’s a lot to look around (at) and people just don’t stay in the seats the whole game,” said Rodrick Oquento, a 49ers season ticket holder from Brisbane who complained about the quiet atmosphere.

The stadium’s field proved to be an embarrassment, as the Niners had to rip out the entire brand-new $1.4 million turf system after the first preseason game in August because it wasn’t playable. The team is currently on its fifth field after having to re-sod parts or all of the turf about once per month during the season, and while players publicly said they were generally fine with the playing surface, big divots and brown patches continued to be visible during Niners games.

Guido said the initial turf problem, caused by a bad sand and soil base that has since been fixed, set off a chain reaction of issues. Each replacement field was called in sooner than scheduled, and hadn’t been growing long enough by the time it was installed.

“We were constantly playing catch up,” Guido said. He said a fresh start with new turf, and a couple of fully grown backup fields in place, should make next year a lot smoother.

The biggest issue earlier in the year was the nightmarish exit from the stadium — it took two hours just to leave some parking lots. But Guido said they’ve made improvements to each lot and the average exit time shrunk to an hour or less by the end of the year, typical for an NFL game.

Guido said the team is considering building new pedestrian bridges to separate the sea of walking fans from cars and trains, adding more exit lanes from parking lots and switching the direction of traffic flow on local streets.

Guido said they’re having a postseason meeting with Santa Clara officials and consultants, and will be holding focus groups with fans before committing to any changes for next year, when season ticket prices will be frozen, as promised years ago. One big change already approved earlier in the year is a switch to all-mobile ticketing for season ticket holders, an option already used by most attendees.

“Across the board we’re taking a look at every single thing we do,” Guido said, “and seeing if we can’t make a tweak or two to make it more efficient.”

Contact Mike Rosenberg at 408-920-5705. Follow him at Twitter.com/RosenbergMerc.