The North London club finally secured their first Premier League title in 22 years in May, but were beaten in the Champions League final by PSG.
It’s widely expected that Arsenal will have a busy summer as they seek to enter an era of dominance under Mikel Arteta.
Speaking about his feelings on the current crop, Henry said to Betway: "I said at the start of the season that this was the first time I could see us winning the league, and I didn’t stutter when I said we must win it.
“Before, there was something missing, but this year they made it happen. Why? Time, investing the right way, and finally, I can relate to the team. There’s something there – the fighting spirit, the big moments – that you can relate to."
Henry believes the hard work is just about to begin, however, explaining the challenge of staying at the top.
"Now you have to build on it. It’s very important to see what you need to add in order to stay competitive," he said.
“It’s also another thing when everyone wants to destroy you, and everyone wants to take that title away from you. If you don’t start well, people are going to question the same things all season again."
"Adjusting and evolving at the top is key," Henry added.
"This is a crucial year because you need to know who’s going to come in, who needs to go, and you need to make the right choices.
“We’ve seen teams who thought that players were going to come and make them better, but it takes time to adjust to the Premier League.
“So what are Arsenal going to do? Getting someone that can adapt straight away to the Premier League and have an instant impact in a team that just won the league is not always easy."