I agree with quite a bit of what Magus' is saying - the gist of it at least.
Is it reasonable to expect a club of our stature - coming off the back of our best PL season in our history - to make at least £15m available to the manager to strengthen? In my opinion, absolutely, it's a no brainer. To that extent, the owners have to be held responsible for a decent degree our exposure since the start of the season (I discount the notion that further funds were available but that Rafa declined to spend them, because it's nonsense). If those funds had been made available, Rafa would have been able to resolve a certain proportion of our lack of squad depth - and that's where the balance between the criticism of his historical transfer dealings and the criticism of our owners in this last window lies. Certainly, IIRC, we were interested in Tevez and Turner before any suggestions of deals for those two myseriously disappeared. Tevez would've been an instant starter, allowing for Gerrard to move back from game one, while Turner would've replaced Skrtel, providing a much needed aerial presence. Two players who probably would have lessened the burden on the rest of the squad - there would still have been some fair potential for dysfunction and that's where I think the critique of Rafa's historical dealings may be brought in i.e. once you've factored in what he ought to have had to spend and who he might have spent it on.
The rule then; funds should be provided when there's good reason to do so, and there was very good reason to do so. That the owners couldn't do so because it wasn't financially viable is a criticism of their ownership credentials and nothing else - they shouldn't have made the commitments they did if they didn't intend to follow them through, and by that I mean promising to support the manager when he needed it.
Then there's three other issues that tie in; the decision to sign Aquilani, the injury situation and the inexplicable demise of our defense.
It was made clear once we'd signed Aquilani that this was a player Rafa had eyed for many months - he'd been lined up early on as Alonso's replacement. It was obvious, then, that he felt this was going to be a very significant signing, one he had to get right for the future of the club - and coming off the back of the best PL season in our history he had every reason to think of the long-term future by not simply confining his thoughts to the start of this season, but to a number of years. Moreover, it was widely accepted by fans and with very good reason, that - with Ronaldo and Tevez moving on, and drastically inferior replacements taking their place - the Manc's would drop down a few notches, and that this would provide a necessary condition for us to overtake them. At the very least then, it seemed unlikely that they'd be capable of stealing a seven point lead by the end of October - even accounting for our need to manage with Masch, Lucas, Spearing and Gerrard in midfield until Aquilani recovered from injury. So it seemed reasonable enough to suggest that we would be able to absorb Alonso's loss for the first two months of the season, if not getting a lead, then certainly keeping within a margin of six points. The gamble to sign Aquilani was premised on this very perspective and so it wasn't 'obviously' an error, nor was it reckless. We might have signed someone else but for the sake of waiting two months - and in light of the above facts - it seemed wiser to sign the player he'd long admired. Indeed, it was circumstance that dictated that we were to miss out on Gareth Barry at the start of the summer - a player I'm convinced would've steadied the ship in midfield without much risk attached at all. Circumstance too has dictated that Aquilani's return to fitness is taking longer than expected - I recall when Chelsea away was being penned in by newkit regulars as his likely debut date. It is doubly unfortunate that during this period of having to make do without the Italian, we've suffered injuries to Torres, Gerrard, Riera and Agger. Further still, and finally, few could've foreseen the ineptness that would stain our defensive record. Of course, it's the responsibility of the management to ensure players perform to their potential but some margin for individually poor form has to be incorporated into our judgments. That both Carra and Skrtel have performed as badly as they have individually could not have been expected by anyone's standard, and it is quite outside of Rafa's sphere of control to remedy that problem directly under the circumstances (couldn't sign anyone - of any note, hadn't a fit replacement). Whether he ought to have shown greater influence in order to try and induce better performances is very hard to tell, all I can be certain of is that there are two players there who've performed well below their best and barring some inexplicable change in our defensive coaching, they as individuals have to take most of the responsibility for the level of their performances. If in Carra's case it's fitness - it's fitness - and fitness is circumstance.
It seems then that a reasonable gamble has been left woefully exposed quite substantially by circumstance, and perhaps partially by managerial error. By managerial error, I refer specifically to the decision to employ Lucas instead of Gerrard in the centre of midfield more often than would have otherwise been desirable from my point of view. Since it seemed perfectly understandable that Rafa shouldn't risk breaking up the partnership of Torres and Gerrard from the beginning, and so effectively necessitating a Lucas-Masch midfield pairing, I can accept the line-ups he selected for at least the Spurs and Stoke games. Spurs because it would gauge how we might function as a team, Stoke because it's Stoke. Lucas didn't do too badly in the Stoke game IIRC, while Torres and Gerrard showed signs of gelling, it didn't seem ludicrous then that Rafa should keep the same team for the next match against Villa - and barring the inclusion of Skrtel for Ayala - he did exactly that. By the end of the Villa game, however, it was becoming if not patently obvious then verging on it - to me at least - that Gerrard would have to revert back to a conventional midfield role, with Benayoun filling in. The Bolton game seemed to crystalise that view, but by then we'd lost as many as we had last season - an urgent situation but clearly a retirevable one. Yet with the games we had approaching and the injury problems that were about to disrupt us, circumstance would gradually expose those early defeats and the selectoral decisions that had apparently defined them. It was unfortunate then that we should have had to play Chelsea as early on as we did, having already borne the blow of two defeats, while the Sunderland game was a culmination of great misfortune - injuries that we couldn't absorb and a howler of a decision that you probably won't see in another ten years of Premier League football.