Two words summs it all up for me : confidence and momentum.
When we gain a little confidence, we start playing well (2005, 2008), and momentum takes over. We've had bugger all of either in the past few years, at regional or international level. Whilst I think Gatland is far from perfect, he's not a miracle worker either, and when the players are making basic errors in every game due to a lack of confidence, we're always gonna loose the tight games.
Gatland's gameplan has to come into the equation aswell, because it simply doesn't suit the players style, however I can see why he's done it to some degree with Fiji and Samoa in our WC pool. He wants to avoid what happened in 2007, where we were all show and no grit. He has failed to find a balance though, and that's a big worry. I also lay some blaim on Rob Howley as attack coach, he was a reletively unprooven coach when he came in to the international set-up and a feel he needs to go back to learn his trade at a region.
I would personally love Nigel Davies as Wales' attack coach. I think you're a little harsh on him Cymro, and are bundling Gareth Jenkins' failings on him, when in fact Wales' attacking threat during Gareth Jenkins' reign was consistently excellent. It was their lack of forward grunt and defence that let them down. We even outscored Fiji on try's in the final game of the 2007 WC by 5-4. I'd argue that we have superior attacking talent at our disposal now aswell. Nigel Davies is also showing his worth at the Scarlets, as they are one of the most exciting teams in Europe. I don't think he's a great head coach yet by any means, but in my eyes he's got prooven credentials as an attack coach. Saying all of that, I doubt he'd give-up his place at the scarlets to become a member of the backroom staff for Wales, especially considering how he was treated by the WRU last time out.
I think the best thing for Dai Young is to take the Wasps position and show what he can do at a different club. The fact that Wasps aren't the European powerhouses they once were is probably a good thing, as it will take some pressure off Young and allow him to attempt to mould a team capable of returning to the top table of European rugby. He's had to deal with alot of pressure during his time with the Blues. He's got alot to proove before he should be considered for the Wales top job.
Whether or not Gatland stays post WC will all depend on how Wales fare in the Summer. If he stays I think he needs to have a shake-up of his backroom staff and the tactics he amploys. If he goes, I have no idea who should take over. I don't think there are any suitable Welsh candidates at the moment.
Edit. One final thing. I'm a little worried that the U20 WC has also shown that the problems we see within Welsh rugby start at a young age. There is no way that group of talented youngsters should have lost to Fiji. I think it shows that whilst we produce plenty of skillful and talented players, that is very rarely combined with the mental toughness required to succeed at the top level. Henson, Hook, Phillips, Biggar, Jon Davies, Gareth Owen etc. etc. have all shown massive promise during their careers, but have all shown mental frailties that have halted their progress to some degree. Matthew Morgan seems to be following a similar path, combining moments of pure genius with complete, well moments of madness, brain farts I suppose. Two recent players who have shown their mental toughness are Sam Warburton and Leigh Halfpenny imo. Nothing seems to faze them, and that's one of the reasons I've been so excited by their potential. And guess what, they were part of an U20's team that finished 4th at a WC, instead of 7th or 8th. I feel our youth system needs adressing, and more emphasis needs to be given to the mental attitudes of our young hopefulls. They shouldn't be so scared of facing NZ that they ship 92 points and fail to register a single point. The past failings of Welsh rugby seems to weigh down heavily on these young players, and they completely freeze when facing NZ, Fiji etc. despite imo having enough talent to genuinely compete.