i'm quite a newbie to sketchup, so my wishlist is quite modest. i just want the sketchup GUI to behave a bit more 'intuitively' by which i mean like the other apps i use every day. most of these specifically relate to using SU on a macbook pro [before someone jumps in with the "use a 47 button mouse" rejoinder].
a few eg.s off the top of my head:
1: hold down spacebar to temporarily switch to the pan tool, so i can quickly move my view of the work area about without having to select a special tool [see almost every other mac graphics/design app]
2: autoscroll my view if i'm dragging an object off the edge of the window.
3: give me some way of resetting my viewpoint to the default so that if i've messed about zooming in or out, changing my field of view etc. etc. i can get back to 'normal' without having to reset everything individuallyy.
4: just make the zoom tool work like it does in almost every other app i use; click to zoom in, alt/option click to zoom out, drag a marquee with the zoom tool to zoom to that area and doubleclick on the zoom tool in the toolbar to view actual size. nice and simple and you only need the one tool to do it all. no need for all these different tools and silly 'push up to zoom in' in, 'pull down to zoom out' stuff, which is really imprecise.
5: make other commonly required stuff like turning on and off guides, and snapping and the like accessible as menu items, rather than making me hunt through preferences and obscure windows.
there are a few more things that bug me, but those'll do for now.
for me, the irony with sketchup is that i find the actual 3D modelling to be the easiest and most intuitive of any 3D app i've come across yet, but the GUI has me tearing my hair out in frustration. i've previously dabbled in cinema 4D, poser, carrara, bryce and [w-a-a-y back in the day] infini-D - and sketchup knocks them all into a cocked hat as regards the speed with which i've been able to pick up the rudiments of modelling with it. however, i feel i'm spending more time switching between tools and setting options than i am actually making models. in day to day life i tend to almost live in photoshop and illustrator and their interfaces are so good and so intuitive, most of the time i hardly even have to think about what tool or option i need next, they're just there where you want them - or an easy keyboard shortcut away.
in summary i guess i'd just like the sketchup team to devote a bit of time into streamlining the interface and making it more user friendly, rather than devoting all their efforts into adding more bells'n'whistles.