Well, this didn't go to plan...
For every great move in the transfer market, there are at least as many bad ones. While it may be too early to write them off completely, the following players have struggled to impress in the first half of the season. For your reading pleasure - or otherwise - we give you the 12 we've been most disappointed by so far this term.
12. Jairo Riedewald (Ajax to Crystal Palace)
Dutch international Jairo Riedewald joined Crystal Palace in July on a 5five-year deal following the appointment of former Ajax and Inter boss Frank de Boer. Adjusting to life without Sam Allardyce, Palace wanted to take the opportunity to radically alter their style of play and Riedewald was seen as integral to De Boer's intentions, having played under him at Amsterdam giants Ajax.
He started in the opening-day defeat to Huddersfield but injury and a change of manager restricted him to just 35 more minutes of Premier League football – until New Year's Eve, when an injury crisis prompted Roy Hodgson to recall him. There's hope yet.
11. Kelechi Iheanacho (Manchester City to Leicester)
After his immediate impact upon promotion into the Manchester City first team in 2015-16, Iheanacho became the poster boy for the Blues' academy. When Leicester City offered £25m last summer for the Nigerian international, the selling club rated him highly enough to insert a buy-back clause reported to be as much as double the transfer fee.
He appeared in nine of Leicester's first 12 Premier League games, albeit mostly from the bench, but he hasn't played a league minute under new boss Claude Puel. The Frenchman has spoken of Iheanacho's need to improve many areas of his game, which doesn't bode well for the young striker who has only found the net once for his new side, in a League Cup game against Leeds.
10. Sandro Ramirez (Malaga to Everton)
Sandro starred for Malaga in La Liga last season, scoring 14 league goals in 30 appearances for the Rosaleda side including a sensational solo effort against former club Barcelona. His ridiculously low release clause of £5.2m reportedly attracted interest from some of Europe's finest clubs – including Real Madrid – so his signing was quite the coup for Ronald Koeman's side.
Sandro has only made three Premier League starts for the club and only found the net once since his move to Merseyside - the consolation in a 5-1 home battering to Italian side Atalanta in the Europa League. If reports are to be believed, new Toffees boss Sam Allardyce is ready to give up on Sandro and has sanctioned a loan move back to La Liga.
9. Kevin Wimmer (Tottenham to Stoke)
With Stoke having conceded more goals in the first half of the season than any other side in any of Europe's top five leagues, it's difficult to truly judge how poor Wimmer has been as an individual when the collective has failed so spectacularly.
That said, he has been part of a defence that has conceded five in games against Chelsea and Spurs and seven against Pep Guardiola's Manchester City, and started the FA Cup loss to League Two side Coventry City that saw Mark Hughes sacked.
8. Joe Hart (Manchester City to West Ham)
England's No.1 for the best part of a decade, Hart was quickly deemed surplus to Pep Guardiola's requirements at Manchester City. A loan spell with Italian side Torino was pockmarked with errors, so when West Ham came in for Hart in the summer it seemed a good fit at the beginning of a World Cup season in which he needs regular first-team football.
Sadly for Hart his erratic form continued and he lost his place to Adrian at the beginning of December, prompting speculation of a window move to Newcastle United with the promise of first-team football.
7. Zlatan Ibrahimovic (Free to Manchester United)
The former Barcelona and PSG striker confounded his critics in a seminal first season in English football last year, but has struggled hugely since his return from a serious knee injury this term.
One of the greatest talents of his generation, capable of things the vast majority of footballers can't even conceive of, he has become what his own manager succinctly called 'a player in his late thirties with a bad knee'.
6. Oliver Burke (RB Leipzig to West Brom)
Scotland international Burke moved to Bundesliga side RB Leipzig being hailed as the next big thing in Scottish football – but left a year later having played just 140 minutes of football in the last four months of the season.
He sought a fresh start with a return to British football, but he's made just one Premier League start. The highlight of West Brom career so far was scoring against Coventry in the League Cup - for the club's academy side in a 2-1 defeat.
5. Roque Mesa (Las Palmas to Swansea)
With the Swansea Way disappearing swiftly into the collective football memory, Roque Mesa joined in the summer from Las Palmas with a reputation of being very neat and tidy midfielder who ensured ball retention and rarely wasted a pass.
The perfect fit for the Swansea of previous seasons, he has been largely anonymous as the Swans have sunk to the bottom of the Premier League table with no discernible style. The appointment of Carlos Carvalhal may see Mesa's importance rise in the second half of the season, but up to now he has been - much like the rest of the team - ineffective at best.
4. Andre Gray (Burnley to Watford)
Hoots of outrage rang around the Burnley fans when the board accepted a bid reportedly north of £11m, but with hindsight it looks a shrewd move. In his first 18 hours or so of Premier League football for Watford, he scored just two goals.
He has started 2018 more brightly, with goals in his first two league games – the latter finally breaking his Vicarage Road duck and helping the Hornets come back from 2-0 down. His own reputation requires a similar rescue effort but he will hope to prove why Watford thought he was worth such a fee in the first place.
3. Renato Sanches (Bayern Munich to Swansea)
It was seen as quite the coup when Swansea signed Sanches, already a champion of Europe with Portugal and winner of the Golden Boy award. It seemed that Paul Clement's friends in high places facilitated an unlikely move for a player who a year before had moved from Benfica to Bayern for an enormous fee.
To say it hasn't worked out would be an understatement. As Swansea slumped to the bottom of the league, Clement paid with his job. For his part, Sanches has featured in the majority of games without nailing down a place: he hasn't started more than three consecutive league fixtures.
2. Gylfi Sigurdsson (Swansea to Everton)
Icelandic international Gylfi Sigurdsson's protracted move over the summer served nobody - least of all the player. At Swansea he was the main man, the creator-in-chief, given licence to play to his strengths. Ronald Koeman's curious variations-on-a-theme summer transfer policy collected Sigurdsson, Wayne Rooney and Davy Klaassen – all at their best in the same No.10 role.
Everton's lackadaisical pursuit of the Icelander meant he arrived at the club too late to be incorporated into pre-season; since then he has been rendered impotent by their early-season form under Koeman, their subsequent spiral under David Unsworth, and an ongoing lack of a decent striker to benefit from Sigurdsson's dead-ball wizardry.
1. Davy Klaassen (Ajax to Everton)
There's an element of risk in any transfer but it seems to be particularly hit-and-miss when Premier League sides look across the North Sea to the Eredivisie. For every Afonso Alves there's a Luis Suarez; for every Altidore a van Nistelrooy.
When Davy Klaassen joijed Everton for £20m in summer, Ronald Koeman assured supporters that the midfielder would "hit the ground running" and cope comfortably with the high tempo of the Premier League.
Koeman couldn't have been more wrong, unless he meant "running away from Goodison". Klaassen hasn't been seen on a Premier League pitch since September, and hasn't even been in a matchday squad since October – except in Everton's calamitous Europa League campaign. There's definitely a very fine player in there somewhere, but it may take a move away from Goodison to refind him.
