I started off adv style riding on a KLX250, and thought it was really great at it.
A bit under powered, but I had a great time traveling on it.
I killed that and went onto an old DR650rs and loved the extra power on the road and it's ability to cart my crap better.
But I did still sometimes wish I was on the KLX, the better handling and suspension were the main things I missed.
After the DR fell apart on me I stumbled on an older KTM 640 Adventure.
I do not miss anything about any bike I have ever had after riding the 640.
Being able to do 130 Kph fully loaded up on gravel roads with ease is something I really enjoy these days, and I have found myself wishing I had more speed on some desert roads I have traveled on with it (160 was the best I had seen on a GPS once, but I don't usually look how fast I am going or carry a GPS).
It has completely changed my style of riding from plodding along just on the speed limit to pretending I'm racing Dakar every time I go on a trip.
I ended up rebuilding the old KLX with the intention of doing a few trips on it, but after riding it again, I sold it because it was just so boring, a trip on it would be a chore...
I have nothing against smaller bikes, I used to preach loudly that they were a lot more capable than people give them credit for, but I could not go back to them for gravel road work.
A KDX is way cooler than what ever you ride...