Still, there's other things and other angles... Lets start with building...
1) Easier building.
I know Strawberry wished for more building talent. I'd turn that upside down. I think building should be easier. Think about Minecraft for a minute! It's dead easy to build in there. Perfection is not within reach, because everything is build from cubes; Mountains, clouds, trees; Even the Avatars look "cubistic". The entire world has an appearance kinda like a lego world on steroids. There will never be sailing there, because there's no wind, no way to make several cubes act like an item, - and there's no scripting language either. The building process, however, it is extremely simple. After five minutes in creative mode I had a house with doors, windows, roof and a terrace overlooking the lake. It all looked like lego, so I won't be staying in Minecraft, but... I hate that I need to go outside SL to build. Make the tools better, and put them inside SL.
2) Better physics.
This one is probably impossible. It relates to sailing. Make the water, the waves, the wind, the physics of moving though - or on - water better. Advanced physics would probably be a selling point, because SL would be a much better gaming ending, - and a much better engine for flight, sailing and driving simulators. What if SL had waves? What if moving stuff through the water caused ripples? What if the wind caused ripples on the ocean surface? It doesn't have to be all about mesh clothing for teenagers does it?
3) Lower tier.
Everyone talks about that. Lower tier would be nice. Talk about product loyalty. What's keeping ppl in SL? The sailing, the people, the parties... lotsa stuff actually. However, if we all had a bit of land, an island or just a piece of dirt in the dessert with our stuff on, - wouldn't that be the single best creator of loyalty? I'd wanna build and rebuild a marina a million times. Hold parties. Test new stuff. Sadly the tier is way to high for that; Much higher than with any budget cloud host. SL must make money, but maybe it could be done differently. How about lowering the tier to get ppl to build houses and stay in the game. Then maybe put a VAT on the markeplace instead. This would boost ppls ability to build their own stuff and put it on the market, and who cares if they take say 10% of each sale? I mean, they are providing the system, are they not?
Hmm... What else?? Better boats ofcourse, but that's entirely up to us; The ppl of SL. Maybe put it on my iPad??