Dalla Vedova would say that wouldn't he? That's what he was being paid to do. Look, I'll tell you what. I'll play 'devils' advocate' and adopt the position Knox and Sollecito are innocent and Guede is the sole perp. So Guede, being a migrant from Africa at age five, was obviously a drifter and n'er-do-well. So on a bank holiday weekend he decides he's going to burgle the cottage of his acquaintances. Instead of entering the easy way, via the boy's roof terrace downstairs, and who are all away, he decides to clamber thirteen feet up a wall after chucking a 10lb sandstone/limestone rock through Filomena's window, via the car park area. Mez arrives home unexpectedly, or maybe she was already at home, with the light from her room at the back of the house, not visible from the side or front. Guede, being a predatory male, makes advances which Mez rejects. So he overwhelms her by force, inflicting 47 wounds plus four neck wounds whilst she was still alive, whilst holding her arms behind her back. Once deceased, after about fifteen minutes of suffering, he rips off her clothes and moves her body by her hair. He takes her rent money, two phones and credit cards, leaving all the laptops, camera and jewellery behind. He fetches AK's lamp from her room and for some reason places it on the floor by Mez' bed. In a moment of great pity, he fetches towels to staunch the blood and covers the body with a duvet. He finds a key to her door and locks it after himself after finally leaving, having left his footprint on the bathmat.. By coincidence, Knox and Sollecito have both switched off their phones but Sollecito denies it, claiming the walls of his apartment stopped pings from the mast. So they come under suspicion.
I've always been amused by your creative writing style...
"Instead of entering the easy way, via the boy's roof terrace downstairs, and who are all away, he decides to clamber thirteen feet up a wall after chucking a 10lb sandstone/limestone rock through Filomena's window, via the car park area."
Well, let's see. How does one get up on the terrace in the first place? Hmmm... it appears you'd have to climb the security grate on the window below it to get up there, which sounds very much the same effort as climbing the security grate under Filomena's window to get up there. So far, it's no easier. Next, there's breaking the window, or are you suggesting the glass french doors should have been what he broke to get into? For Filomena's window, all he had to do was toss the rock from the parking area parapet. If he broke in from the terrace, he'd have had to carry the rock up with him as there was no easy way to throw the rock from the ground. And, of course, this creates another problem. If someone is home it's easy to just run from the parapet, but if he's up on the terrace, getting away is much harder. In fact, the only thing that would be easier from the terrace would be climbing in through the window, but only slightly, and it certainly does not offset the harder aspects of getting onto the terrace and getting away if someone is home.
There was nothing about how Meredith was murdered that made it more difficult for a lone assailant that any of the hundreds of thousands of other females murdered by a lone male assailant.
"Once deceased, after about fifteen minutes of suffering, he rips off her clothes and moves her body by her hair."
I see no evidence that suggests her clothes didn't come off until she was deceased. In fact, I believe the aspirated blood droplets on her bare breasts is proof she was in fact still alive when she was undressed. Further, there is no evidence she was moved after death, nor is there any evidence it was by pulling her hair.
"He takes her rent money, two phones and credit cards, leaving all the laptops, camera and jewellery behind."
He finally did something smart, as taking those other items would link him to the murder. He apparently realized the same was true with the cell phones, which is why he tossed those, but cash is easily spent without tracing.
"In a moment of great pity, he fetches towels to staunch the blood and covers the body with a duvet."
I don't think it was pity, nor do I think he was trying to staunch the blood. But whatever the motive, he did fetch the towel and cover her body with the duvet.
OK, so what's the problem here?... I think, despite your somewhat creative writing style, and the questionable comments I've noted above, you summed things up pretty well.