I don't think, bless him, that Elton's behaviour has matured all that much recently - try reading the reviews from people at various shows in Las Vegas last year when he threw tantrums, cut short performances etc or listen to his foul mouthed rant against Madonna by way of example. The big step forward was about 15 - 20 years ago when he got most of his addictions under control to his enormous credit (and possibly David's too!) but his oft witnessed public behaviour with fans and within the industry suggest he remains an unpredicatable egotist who considers his wants and needs override other people's. In itself, that is nothing to do with him being a parent - it's a common problem with supremely talented entertainers who have had their every whim pandered to all their lives and I would be the last person to suggest they are not, all things being equal, capable of being adequate parents (especially if the other parent is able to compensate). But to suggest that Elton is in some way a fundamentally 'reformed' or different character from when he was a young or even middle aged man is simply ignoring the facts as we are aware of them.
I'm not disagreeing with a lot of the above as far as Elton himself is concerned (he IS a hissy-fitter and I don't see that changing, I think it's very much part and parcel of who he is) but it also doesn't mean that he hasn't grown up in other ways and is not a good, conscientious and responsible father. And really, Madonna is just as much a self-involved hissy-fitter as Elton but I also think she's shown herself to be a good conscientious mother so... really, your points are moot, no?