Input shaft - life left or replace?

The only input shaft, since 1970, that I have ever replaced had all the teeth ripped off it.................. by me, lol.
I can make those clutch-teeth, in the pic, fully operational in under 5 minutes. But fixing the slider takes a lil longer, and the brass ring will need a new home.

I rarely replace the brass rings, I just shuffle them around to new locations, until they just sit too low on the brake-cones. However, on the input gear, the brass usually sits quite far away from the slider, and if allowed to wear out, it will eventually decouple from the struts, and spin, which will make catching fourth gear a real challenge, lol.
So then, during a rebuild, I try to always give the highest sitting brass to the input.
But for a streeter it hardly matters cuz going into fourth with 3.55s is like over 90mph. Which if Smokey catches me, means I would automatically lose my Driving privileges.

BTW-1,
having rebuilt hundreds of those transmissions, I can tell you that the degree of pointiness, with a good-working brass-ring, hardly makes a difference.
However, once a slider tends to kick into neutral, under power, it's game over, the trans has to come down; and all all of the teeth will need to be back-cut on the power side.
But, if it kicks out under deceleration, there are usually no more than two sets of four of them involved in kicking out; so those eight will need to be back-cut.
Exactly which teeth will need to be cut, will be evidenced.
I do this with a hand-held electric die-grinder like a "dremel" but with a longer nose on it that is able to operate at a better and deeper angle. I use a tiny cut-off-type wheel, about 1inch in diameter, if you want to try it.
No, I do not use an air-die grinder, which are too difficult to maintain speed with, at anything but WOT, so half the time is spent, waiting for the grinder to come back up to speed.....................................................
Actually, it's more about personal preference, lol.

BTW-2
you may need to keep after your free-play adjustment more often, as this damage occurs when the brass cannot do it's job anymore, usually because the stinking disc won't stop spinning, usually caused by a lack of departure.......
but could be a bent disc, or a release finger out of adjustment, neither of which is common. Or, if you have short legs, lol, and just don't push far enough, jussaying.