As a long-ago dirt bike rider shopping for his first street bike I may be talking out of the wrong orifice, but I'd definitely vote for an 800 or 850, putting out 80 or 85 hp.
If Mr. Suzuki is reading this, I'm basing my ideas on the factors that might make me buy a KLR or a G650GS instead of a V-Strom.
Being a street-bike rookie I look at this from a slightly different perspective. I sometimes wonder if the 650 is going to be a little too powerful for me to start with, but I also fear that after 6-12 months it won't be quite powerful enough for my heavy carcass and garage-door aerodynamics. The 1000 is probably a little more than I would ever need, and would be a little too expensive to run for a daily commuter; an 800 would fill all my long-term requirements.
It seems to me the ideal 800 would have a switch that changed the fuel-injection mapping on the fly, leaning out the mixture and reducing the power output to something in the 50-60 hp range. This would make the Strom 800 the ideal entry bike: not so much power that you wind up upside-down on the road, and not so underpowered that you want to trade it in when you're still upside-down on your loan.
It would also come in handy for riders who want to save on gas and rear tires, like some of the earlier commenters. That 60+ mpg some people get out of the 50hp G650GS is awfully tempting; it'd be even better if I could get 80hp and 45 mpg out of the same bike when I felt the need. I believe the Hayabusa and B-King already have a similar switch, so Mr. Suzuki already has the basic technology on hand.
I'd also vote for an updated (i.e, better-looking) front end, more appealing color options, and something with lower maintenance needs than a plain ol' chain. All of my options have chains, and the idea of oiling, checking and re-tensioning a chain isn't something about which I'm terribly enthusiastic. The idea of a belt on a sport version and a chain on an adventure version makes sense.
Offer ABS (can't figure why it's not on the 1000), and see about providing a little more stopping power. Can't you just take the front calipers out of that bin labeled "GSX"?
Keep the seat height (unless you want to raise it--it seems kinda low to me!
). The fuel capacity should stay the same, but it would be cool if you could put it 2 or 3 inches closer to the ground without lowering the seat.
It seems like this year's lull in production is a perfect opportunity for Suzuki to trim costs by consolidating the 650 and the 1000 into a single bike, especially if some of the engine parts can come from the C50/M50.