Bad shifter feel

[DrBacon]

So I bought my 370z nismo used last year at around 25,000 miles, and I was informed the clutch was replaced when I bought the car. Over time the shifter (or it's my imagination) seems to be feeling worse, more clunky and rough. I've had the transmission fluid changed with redline mt-85 a few months back and its made no difference in the feel at all. I've been doing some research and apparently there's a lockout where you have to physically press down on the shifter to enter reverse? I've actually not known this, as all I have to do to enter reverse is just push straight right and then down to reverse (although with a bit more force than it would take to enter other gears). Is something messed up which is contributing to my really poor shifter feel and missing reverse lockout?