Make the steering lighter?? Whaaa!? The steering is variable, proportional that gives you proper feedback, not vague. If it is working right then it will be correct.
Do you have oversized tires? wheel hub spacers?
It could be possible that the proportional valve is not working. I would do a VCDS scan to see if there are any steering or ABS problems or wheel speed sensor errors

 

does it center itself after a turn?

 

Time to hit the gym a little son!
You could also install a "bus size" steering wheel to get more leverage.
Run pizza cutter style tires.... narrow cross section.
Run LRR tires, or very hard compound\high wear units.

 

Why do have to beat the OP up ? He is asking a question of the forum to gain some insight into what his impression of the steering on the highway

 

Toe out can cause a heavier steering feel, low tire pressure can do the same, low fluid can cause overheating and a similar feel, play in a wheel bearing allowing the wheel to "move" around can do this. Worn bushings or a loose rack can eat movement and feel same. Just some ideas not model specific as I am new to this vehicle.

Actual answers can help sometimes, jokes can help but just e-thugging to e thug is low.

"oh but noobs need to search" - if you are going to poke its the same to actually answer.
"i have xx years of exp" - same as above
"do your own research" - I am sure you knew what loan amortization was the first time you got one and didnt just nod when they asked if you got it.
"i am tired of . . ." - then dont, engage for the better or to discuss.

 

When you nannies finish beating me up for e-thugging, read the OP's post and my post.
He is after some mods he could make as he's already confirmed pressures and fluid levels.
As such, all of my answers were appropriate, even if the first one could be taken as "offensive" by some snowflakes.

OP, in between preacher curl sets, check out your tire wear.
If you have an alignment issue, you should be able to notice it through funny tire wear.