Honestly, I don't think the future of bitcoin is running "heavy" nodes on our personal computers.
I think the vast majority of people will be using bitcoin through web or mobile apps in the not-too-distant future. So I'm not personally inclined to put a lot of effort into splitting the node and wallet, unless that makes creating lightweight web and mobile apps easier.
That said, the new QT gui does a much, much better job of letting you know what bitcoin is doing, both during initial startup and initial blockchain download.
I do think it would make creating lightweight web and mobile apps much easier. Wallet apps, whether desktop or mobile, wouldn't need to deal with connecting directly to the p2p network or with managing the block chain. They could use the proven c++ codebase for that.
There are problems with using the current wallet for the implementation of web based, hosted wallets (chief among them is the inability to handle key creation and transaction signing outside of the bitcoin process). By separating the wallet and client, you could decouple their evolution with some people focusing on making a really good p2p client and others working on the wallet code. The wallet side could itself evolve into a daemon that supported both desktop and web based UIs. And other projects building wallets could benefit from being able to use the proven c++ client for the interface to the block chain and p2p network. I also foresee the need to have substantially different types of wallet implementations (imagine a company needing to manage its funds...the wallet UI for those users may need to be completely different...allowing for a workflow where multiple signatures are required to spend funds and such).