I like scooters, I have 3, a Yamaha Vino 125 and Zuma 125, and a Genuine Stella 2 stroke. They are a lot of fun, but they may as well not have any suspension. I have a bad back, and everytime I hit a bump, which is quite often around here, they pound my back like a jackhammer. Because your feet are out in front of you, it is difficult to raise yourself off the seat when you see a bump coming.
Last thing, I would check into the maintenance requirements. Some maxi scooters have ridiculously high maintenance costs. Especially check the valve adjustment intervals and procedure. I chose the Zuma 125 over the Honda PCX150 because it takes 15 minutes to do the valves on the Zuma, and 3 hours on the PCX. Apparently you have to remove the whole body and pull the motor to get to the valves on a Majesty. Dealer book says 6 hours labor. Not sure about the Burgman. But definitely something to consider.
If comfort is your main concern, you might want to look at a cruiser, although modern cruisers are not as comfortable as the older ones. The Vulcan 750 is a 1985 design. Newer ones are designed more for looks.
Jerry brings up some good points.
First, I doubt that any scooter will ride as well on rough roads as the KLR. It's hard to compete with 9 inches of suspension travel. Also, it's more difficult to get your weight off your butt when you see a large bump coming.
Maintenance. Likely to be higher on the scooter. My KLR gets 50MPG, my scooters 75. The KLR is probably still cheaper to operate due to the much lower cost of tires. It also requires less overall maintenance.
Comfort is subjective but overall you will probably be more comfortable on a scooter except on rough roads. Keep in mind that that maxi scooters don't all have the same riding position. I have sat on all of them and the SW and Majesty don't work for me while the Burgman is OK. You may find the opposite.
You really won't know if a scooter will work for you until you try one. I'd recommend getting a used scooter and keeping the KLR. Later, you can make a decision on which to keep, or maybe sell both and get the new BMW Scooter
Or better yet, keep the KLR and get a small scooter and a maxi scooter