Most high-end radio's have a progressive rate tension on the steering.
That is, the further you turn.. the more pressure is required. This is done via a cam that lifts a spring loaded tension bar. (Connected to a linear coil spring)
This helps keep the centre weight low and very smooth.
However, if you can adjust the tension on your radio then you can turn it down to try to make the centre return less strong. This will however, make the entire steering throw very light.
It's all about compromise...
Other things to try -
If your radio is old, have a look inside the case. (Hey.. I'm not responsible if your turn your radio into junk, or you void your warrantee.. so beware!)
If the radio is old - some of the lubricating grease may have migrated away.
Just spot the old grease and re-lube with ELECTONICS sepcific grease. This grease does not evaporate and leave residue on teh electrical parts.
Please don't use regular grease..
Those high-end radio's aren't cheap.. but they are a step up in every respect, over a cheaper radio. Some people would have the extra $$ for the improved feel alone.