I find the opposite to be true. I cant even think about going back to the riding position of an Apex after riding "modern" sleds. I get the chance to ride an Apex and Rage/Vector every now and again. I also have owned a RX-1, Apex, Phazer, Nytro and A Rage. Its the seating position/front end that always stand out as being the things that needs the biggest improvement. No question the engine and running gear are stellar. Suspension and handling? Not so much.
Not sure how tall you are but the shorter people seem to be able to ride the older sit down sleds easier.
They don't make sleds with that style of riding position any more. The reason? There are better options. In fact, no other type of vehicle makes you sit in that position, on your tail bone.