My SV650 Adventure build puts out around 65HP and weights 156kg/345lbs ready to ride with it's (16 liters / 4.2gal) fuel tank somewhat more than half filled.
If I add a front fairing + bracketry (adds weight) and replace the (steel) fuel tank with a composite underseat tank (loses weight), the total weight won't change all that much.
So yes, the bike pictured above would be very well doable for KTM. In fact, I wonder where all that extra weight of the LC8 Adventure compared to the LC4-640 Adventure comes from. Those two bikes are comparable in 'features' and the LC8 engine isn't that much heavier than the LC4-640 engine. I guess it just adds up; a little extra weight in the wheels to handle 100HP, a little extra weight in the swingarm to handle 100HP, a little extra weight in the frame for those 100HP, heavier chain and sprockets, and the list goes on.
Which also means that I probably don't want 90-ish HP, but more somewhere around 65hp. Makes the chassis lighter; less material needed to put all those horses on the road. And less horses to feed means more miles per gallon, which saves weight too.
65HP in such a light chassis is more than enough to be above the speed limit within seconds from standstill, it is enough to carry a pillion and still have fun on twisty and steep mountain roads, and 65 horses can get you into trouble real quick when going offroad.