everything is possible.... it's only software!
However, keep in mind that adding features to SWA always means working on the edge of adding too much, making a thin client thick, etc. One of the reasons that people are moving away from Outlook is that it has too many capabilities and too much choice; the nightmarish epic options dialog is a black hole of information to no avail.
Therefore, I'd not really want to try to replicate all features Outlook is offering. I personally don't customize views and I've never done it, neither in Outlook nor in SWA. Now, I'm maybe not your typical user (though my email volume is high), so... why don't you suggest specific additions to the layouts or layout options, with hopefully good reason. Don't say - like Outlook, that wouldn't get anybody anywhere, at least that's what I think.
For specifid things, you might also open up an enhancement request in Scalix Bugzilla. If enough people are interested in a certain specific features, we'll certainly be happy to look at it.
Florian.