Deans is poised to be named as the coach of the Barbarians side to face the All Blacks at Twickenham in November so has a direct interest in analysing how Gatland's side are evolving in their bid to record a first Lions Test series victory in New Zealand since 1971.
He believes the Lions' hopes are founded on the unprecedented intensity of the tour against the Super Rugby franchises - which should ensure the tourists are more prepared for opening Test than they were four years ago when he was in charge of Australia.
"I think the Lions will be happy with the guys that they have taken and most importantly they have been galvanising as a group," said Deans. "They are aware of the size of the challenge ahead of them and the cauldron they have gone into.
"There is no respite. This tour is unprecedented really. The fact that the Lions have had to play the Super Rugby franchises for the first time has resulted in them facing really tough and well-established combinations. There is absolutely no let up.
"I think that will have worked in the Lions favour because they are going into that first Test having been burned into shape. They will be hardened and that will be the challenge for the All Blacks. They have only had a week to get up to the same point of intensity.
"The Lions will be much more battle-hardened than they were in 2013. It can only help them getting to a level of performance that will be required in the Test match."
History however is against the Lions. The All Blacks have not lost at Eden Park since 1994 and Deans claims there is an aura about the stadium that tends to overwhelm opponents.
"To succeed at Eden Park you need to have an unwavering commitment," Deans added.
"It is part of the history and the accountability. The players have the greatest responsibility not just for what has gone before but also the teams that will follow. That is it in a nutshell. A fair amount of belief comes forward because of the history.
"They find ways to win as their opponents find ways to bottle it and ways to lose. To succeed there you have to turn up to prepare for the very last play and enough commitment to sustain the pressure because if you relax or relent for a moment, you are in trouble."
Gatland's Lions are unlikely to relax or relent, but the question that has followed the tourists around New Zealand over the last four weeks is whether or not their game plan is enough to challenge the world champions.
The Kiwi media and public have criticised the Lions lack of attacking prowess, but Deans believes Gatland should not be deterred from playing to his side's strengths.
"Style is irrelevant," Deans added. "At the end of the series there will be an outcome. That is all that will be recorded. And it is all that deep down people care about. Obviously if you can do it with style as well, that is a bonus. But deep down most supporters would say they want the outcome.
"Both teams will play to their strengths, and also attempt to bring an element of surprise in order to unlock the game.
"The Lions will have to create pressure to succeed. They will have their own ideas on how to do that. People talk about the Lions kicking game but the All Blacks also have a very good kicking game and create a lot of pressure off the back of their 10.
"In terms of outcome, people do not sit there and count the number of kicks. The All Blacks kick the ball more than most teams. The difference is how they kick, when they kick and what benefit they derive from kicking. That is the critical question."
Yet if Deans believes the Lions can "win the hearts and minds" of the New Zealand public by their competitiveness, the former Crusaders coach can only see one result in the series, a blackwash for the Lions.
"To be fair, the All Blacks will be most vulnerable in the first Test when they are at their most rusty. It is a great opportunity for the Lions. They will know how to go about it as well. The challenge is to deny the All Blacks the possession they enjoy, if they don't, they simply won't do it.
"They will have to go out with the mindset of believing and play the game of their life. If they do that they have a chance but they must turn the scoreboard over.
"Ultimately though I predict the All Blacks will win 3-0 because I believe that is what they should do but I don't believe it will be as straightforward as people expect. They won't have things all their own way."
