Coach Trevor Bayliss says England's one-day team have an "exciting future" after a summer that has seen a dramatic improvement from a dismal World Cup.
England beat World Cup finalists New Zealand 3-2 in June and pushed world champions Australia before defeat in Sunday's decider sealed a 3-2 defeat.
"The development of some individuals has come a long way," said Bayliss.
"There are some exciting young players in the England set-up and it will be an exciting future."
England came from 2-0 down to force a decider at Old Trafford, but slumped to 138 to allow Australia a simple chase to an eight-wicket victory.
However, a competitive series against Australia and victory over New Zealand came with performances far removed from a first-round exit at the World Cup, which included a defeat by Bangladesh and victories against only Scotland and Afghanistan.
A change of personnel…
England's XI for the final defeat by Australia included only four of their 15-man World Cup squad, albeit with Joe Root, Jos Buttler and Steven Finn rested.
Alastair Cook, dropped before the World Cup, and Ian Bell have been moved on from the top of the order, replaced by Alex Hales and Jason Roy, while experienced pace bowlers Stuart Broad and James Anderson have given way to the likes of Mark Wood, David Willey and Reece Topley, who made his debut at Old Trafford.
Ben Stokes, omitted from the World Cup squad, has established himself in the all-rounder's role, while Adil Rashid provides a wicket-taking threat with his leg-breaks.
"Some of the individual players who have stepped up and taken their game to another level have been outstanding," Bayliss told Test Match Special.
"The bowling of the spinners has come on in leaps and bounds. Jason Roy, at the top of the order, has proved he is a very good player.
"Ben Stokes is maturing as a cricketer, not just on but off the field as well.
"I'm impressed by young Topley - it wasn't necessarily his day today but going forward he has some very good skills to work with."
In choosing the likes of Roy and Willey, former England captain Michael Vaughan believes England have benefitted from using players who specialise in limited-overs cricket.
"It looks to me now as if the focus is very much on who are England's best one-day cricketers," said Vaughan. "For the first time, we might see five or six real one-day specialists in the side."
...and a change of approach
The most obvious change to England's one-day cricket has been their approach to batting, with a World Cup run-rate of 5.48 being upped to 6.63 across the 10 games against New Zealand and Australia.
They posted their first ODI score in excess of 400 against New Zealand, then completed their highest chase of 350, before following that up with a pursuit of 300 in the fourth match against Australia.
"The selections suggest the sort of personnel that they want, which is a far more aggressive type of player, free players with the bat," said former England off-spinner Vic Marks.
"It's all very well saying you are going to play freely, but if you've not got the players in your team who are instinctively like that, you can't do it."
England's poor World Cup contributed to the sacking of coach Peter Moores, with the refreshed approach to the one-day game beginning when Paul Farbrace took temporary charge for the series against New Zealand.
"At the World Cup, you'd hear Moores say 'I'd like my team to play fearlessly', but they couldn't do it," added Marks.
"Almost the identical words were spoken by Farbrace, but somehow those words seem to have got through."
But there's still room for improvement
For all the strides they have made, England still lost on home soil to an Australia side that itself had only four survivors from the World Cup final in March.
Strong showings in the next two global 50-over tournaments - the 2017 Champions Trophy and 2019 World Cup - will be expected from England, the host nation of both, and Bayliss admitted there is still plenty of room for improvement.
"There's definitely still work to be done," said the Australian. "We've shown people how well we can play, but days like today, to be the best in the world, you have to play some smart cricket. That comes with experience."
Marks also highlighted some naivety in England's play as well as the need to take wickets with the new ball.
"They need a bit more match awareness," he said. "It's tough if you set yourself to play fearlessly and get the balance between that and playing intelligently.
"In 50-over cricket you have to get early wickets and there have been times when England have struggled to do that. There's not much movement in those early overs, expect from Willey."
As England slumped to defeat in their final international match of the summer, readers of BBC Sport's live text commentary voted in their thousands as to their favourite single moment of the last four months.
Stuart Broad's first over in the fourth Ashes Test at Trent Bridge, when he dismissed Chris Rogers and Steve Smith, registered more than half of the vote, with Ben Stokes' catch to dismiss Adam Voges a distant second.
There were some who favoured Brad Haddin's drop of Joe Root in the first Test at Cardiff and Ben Stokes' 85-ball century at Lord's - the fastest scored in a Test at HQ - while Glenn Maxwell's stunning juggling boundary catch in the fourth one-day international attracted 7% of the vote.