Saying that Txiki has failed is harsh I feel (especially as he's only been here 2 years) his entire list of signings:
Jesus Navas (£14m)
Navas has been a very useful player and the only player with pure pace, and although he gets a hard time on here you cant deny he gives us something different from the rest of our winger/ playmakers
Fernandinho (£30m)
Probably City's best CM considering Yaya only wants to go forward, a great pick
Alvaro Negredo (£20m)
without a doubt helped us to win the league last season, although the second half of his season was poor i'm sure most strikers would take 26 goals in their debut season, and if not for his troubles in Manchester i'm sure he'd still be here.
Stevan Jovetic (£24m)
The only big money signing of Txiki's I feel will never truly fit in, a good player but not the right fit, however I do remember people saying before we signed him that he would be the next big thing, so you cant call for a signing and then when they don't work out blame someone for actually having signed them.
Martin Demichelis (£4m)
Probably been City's most consistent CB this season and barring his shocking first half a season he's been great
Bacary Sagna (Free)
Been good since coming in and you cant really argue with bringing him in for nothing, and i'm sure Micah would've stayed had it not been for his unfortunate string of injuries.
Willy Caballero (£6m)
Very clearly just a back up, although a lot was made of how good he was, still a level below Joe, but a better No.2 than Pantilllimon
Bruno Zuculini (£1.5m)
Not really seen enough of him to argue either way, did look impressive in pre-season though and is still only 20/21
Eliaquim Mangala (£32m)
Shown glimpses of what he can become and if he achieves it he could be VK's partner for a long time to come
Wilfried Bony (£25m)
Not really given too much of a chance yet apart from one start in which he played very well
From these signings I have to agree that in reality they were only ever meant to pad out the squad, I imagine in preparation for this summer, due to the restrictions imposed, its ok saying that our squad hasn't changed since 2011 or whatever but they were bought with no restriction and how much of the money spent around that time was wasted? £20m for Roque Santa Cruz? £22m for Joleon? £18m for Jo?
I think that Txiki's defining summer will be this one (if your to believe the likes of Tolmie, which I do) and hopefully he will have built the core of the squad for years to come.