Lets face it, the only reason 800cc came to light is that the Moto GP went to 800cc.
that's quite the stretch. let's see....
BMW had the 800 twin on the streets in 2006. iirc, Nicky was champ on the 990 that year.
vfr800 dates back to '98.
tdm800 to, what, '92?
nevermind all the 800cc Bonnies Triumph has had out recently.
Ducati has had air-cooled 800s on the street as well.
besides, you'd have to be one helluva marketeer to connect a d-s-ish bike to GP machinery.... especially when you don't build any GP machinery.
GP bikes are peaky because they are 800cc fours that make 240hp. motors get "peaky" when the bore/stroke ratio gets really high, as is required to reach 18k rpm or whatever level of the stratosphere GP bikes reach. bore/stroke ratio on the triumph 800 will not be that high, since they are not able to bore it out that much (if at all). the displacement increase is due to stroke, which will lower the ratio, increasing torque. the bike will have a broader powerband than the donor 675.
an 800cc triple making ~100 Hp will have a nice broad powerband, like a versys but with more meat. i say this based on 40kmi on my vfr, which had a nice powerband. that bike had a bore/stroke ratio of 1.50. based on some quick calculations, the 800 triple will be similar. if the stroke stays exactly the same as it is in the 675 and they punched it out from 74 to 80mm (which would be a huge change), the ratio would only be 1.53 (788cc). that's not too far out there. but as i said, they will stroke it (they are not idiots) and the ratio will be ~1.4. you can quote me.
for reference, versys bore/stroke = 1.38.