Much of the sting is taken out of Jesus' teaching when we persist in focussing on children as God's 'little ones', rather than the whole range of powerless & oppressed Jesus' sweep includes. It's a cop out. As well as believing in the existence in some form of guardian angels for any & all the world's little ones who gaze on God's face in heaven, isn't it time for us to become guardian angels for them & bring 'heaven' down to earth a bit? Heaven being 'up there somewhere' is too easy an escape hatch from earthly responsibility towards 'little ones' anyone else.
The Hebrews (e.g. in Tobit), & earlier Christians (witness their art works) took guardian angels much more seriously than we do in our post-modernist society. As a small boy I remember hearing a very old, devout lady whom we used to visit tell me she was sad but not worried that my friend, her young grand-daughter, had died because she had actually seen her young Jean's guardian angel come to stand beside her & look after her! That still moves me & empowers me after 60+ years! Personally, I take my guardian angel(s) very seriously indeed. Debunk them, & we lose out in more ways than one. Become one, in another sense, & everybody's a winner!
"It's not God's will", says Jesus, "that any of these little ones be lost". But they are. In many senses. All the time. When we can't tear ourselves away from the comfort of the fold, our 'in' people, to reach out to the lost out there somewhere in those margins. (Mind you, I wonder today whether Jesus mightn't have to reverse his arithmetic relating to losts & founds!)
The techniques, dynamics, for healing rifts within the Body are not often put into practice on as simple & direct a basis as Jesus sets out here. Most churches, if they make provision at all, rely on laws & structures to cement relationships. All that often does is set poor & broken relationships in concrete! In the context of this passage, it's not hard to imagine Jesus shaking his head in disbelief that we don't relate to each other as he intends. Even Paul came down from his theological high horses to get the Body-language right! The heavy handed approach is the last resort, not a first. Body relationships is a prime example of G.K.Chesterton's "Christianity has not been tried & found wanting; it's been found difficult & not tried!"
Is what Jesus says here about God doing what those who gather in his (Jesus') name ask for more a commentary on what he's been saying about in-house relationships than an invitation to a shopping list approach to prayer? The principle remains that where God is present, there God's will is done. If we gather in Jesus' name, as his Body, & he is present, then it follows that............