I am genuinely baffled by the fact that we have Everton fans who still rate Martinez.
As others have pointed out, Martinez inherited a squad that had averaged fairly high league placings in the previous decade. Admittedly some were past their peak form, but that's true of most squads outside the mega-moneyed clubs; there's a mixture of age ranges. What did Martinez do? He extended the contracts of Hibbert and Gibson - was that a wise use of our resources? It didn't need a genius to see that 37 year old Distin couldn't continue much longer, but his loss of form seemed to take Martinez totally by surprise. Tim Howard had served us well in the main, but he was another who was manifestly getting to the end of his days. Despite Martinez admitting that we needed another keeper, no action was taken. In his last season, Baines, Barry and Jagielka were clearly entering the last stages of their Premiership careers - were they replaced? You could argue that Galloway and Holgate were long term replacements but we needed a couple of experienced Premiership players at the peak of their career. Instead we got Funes Mori, Niasse and Tarashaj.
He couldn't organise a defence at Wigan, and showed that he still can't, even with better players.
Martinez had more money to spend than any previous manager in the Premiership era; that's even allowing for player price inflation.
Recruitment - does anyone - I mean anyone at all - think that this part of Martinez's tenure was a success? Player transfers are obviously a major part of this, but also in terms of the backroom staff. Martinez brought in wholesale a management team that had just overseen Wigan's relegation. How do you think seasoned internationals like Jagielka, Baines, Coleman and others felt about being coached by Dennis Lawrence, whose playing career was spent with lower division clubs? Didn't he also get rid of some of our medical staff? I can well remember the plague of minor injuries which affected the team in his second season. Was this bad luck or something else? Remember Roy Keane's comments about the fact that our Irish players seem to be injured all the time.
Another point - match fitness. It's generally accepted that the team's fitness levels dropped significantly under RM. I remember he blamed the World Cup for this - strange that other teams weren't affected to the same degree.
Over-hyping players - "the best squad for decades"; Barkley "potentially better than Gascoine"; Gareth Barry "one of England's greatest ever players"; McGeady "phenomenal". Did this kind of manifest rubbish help or hinder us?
Transfers. No manager is 100% successful in the transfer market, of course, and Martinez has had some hits, like Lukaku. However, his failures have far outnumbered the successes. Tarashaj hasn't played a single minute for us, for example. Signing total flops like Alcaraz, Kone, McGeady and most of all Niasse - these alone should settle any argument about Martinez's competence.
Some people say we were good to watch under Roberto. While there were good spells, particularly in his first season, there were many poor games even then, such as the 4 - 0 drubbing at Anfield, losing 4 - 1 to Arsenal in the cup, bottling matches towards the end of the season when we had a chance of success. As for the last two seasons, there were more dull games than good ones by a considerable margin. Remember our home record last season - the worst in our history, I believe.
As for those who say we'd have been better off keeping Martinez - did you truly want Martinez to sign another three or four Oumar Niasses in the summer?