Middleton's side, the favourites going into Saturday's final, slipped to a 34-31 loss at the hands of tournament hosts and defending champions New Zealand at Eden Park in a repeat of the 2017 final.
England have won the title twice in eight appearances in the tournament decider, but Middleton was more upbeat after the loss in Auckland than he was following the defeat in Belfast in the previous final.
"We sat here five years ago, a very similar situation but I felt very much different five years ago," he said.
"I feel hugely positive about what we've just witnessed. I don't think we could have asked a single thing more of our players. I don't think we could have prepped any better. I think we played really well in the tournament.
"I thought we played really well tonight. We just came unstuck against a side that just had a bit more than us, and full credit to all the Black Ferns and all their staff. They are worthy world champions."
Middleton has led the Red Roses at back-to-back World Cup finals, but would not say whether he would remain in charge in 2025, when England will host the tournament.
"There's only one thing I want to face right now, and that is a room full of Red Roses with a drink in their hand and celebrating what we've just done over the last 51 days," he said.
"We've got loads of the support from (England's Rugby Football Union) over here who've been absolutely brilliant and we're all going to get together and we're going to celebrate a brilliant team."
