Gatland 'would have avoided Wales return' due to extent of problems
The New Zealander enjoyed an successful first spell in charge from 2007 to 2019, masterminding Six Nations titles, Grand Slams and reaching two World Cup semi-finals.
He replaced Wayne Pivac six months ago but oversaw a miserable Six Nations campaign in which Wales recorded a solitary win.
Rugby in Wales is currently overshadowed by a series of off-field issues.
Allegations of sexism, racism and homophobia within the Welsh Rugby Union are currently the subject of an independent review.
Wales players threatened strike action over contract issues earlier this year, while financial troubles continue to engulf the professional game.
"When I came into the Six Nations, I had no idea," Gatland told the BBC's Scrum V podcast.
"I didn't realise a lot of the things that were going on and the issues that were behind rugby and the squad and the players.
"At the time if I had known, I would have made a different decision and probably gone somewhere else."
Gatland said the success of the national team in the past had "papered over the cracks".
"Now, probably for the better, they have come to the fore and there is a chance to focus on the things that needed fixing," he added. "There's a great chance for us to have a really positive reset on a number of things."
Veteran players Alun Wyn Jones, Justin Tipuric and Rhys Webb have all retired from Test rugby before the World Cup in France, which starts in September, giving Gatland another headache.
But he said he was motivated by the challenge.
"What gives me an edge or a buzz is when the expectations aren't there or the challenges appear to be greater," he said. "That drives me even more.
"It (being written off) is allowing us to come in under the radar, and there is nothing the Welsh boys love better than being written off and backs to the wall. They tend to respond to that."