Tires. Get different tires! I'm installing today the second set of Pirelli Scorpion Trail II on my 2015 V650. They are much better at everything than the factory tires. There is a whole range of tire options out there, from knobbies to highway to dual sport. Factory tires suck pretty bad at everything imho.
I replaced the front turn signals with micro size LED signals. They don't hit the ground. R&G Racing sells some nice ones and the mounting adapter you'll need.
The seat bothers some due to the forward lean. You can shim the nose of the seat up with something homemade or buy a cheap plastic gizmo someone here is making on a 3D printer, or you can get an aftermarket seat.
There are a lot of adjustments you can make to the ergonomics with handlebar risers to move the bars up and/or back, lower the foot pegs, lower the suspension overall, etc. A lot of people go to a larger windshield.