I did some thinking about this, and the simple fact is that Point Defense Reroute isn't worth taking under any circumstances.

The card has the following rules:

When attacking a squadron within close range, you may reroll your CRIT icons.

Let's break this down.

First off, it's limited to close range. Anti-squadron dice have a medium range typically.

Second off, it's limited to rerolling crit icons. Ergo, only 50% of the misses on blue dice can be rerolled. None of the misses on black dice in Wave 2 ships' anti-squadron armament can be rerolled (There's no point in rerolling crits on black dice because those faces also have a hit symbol. Black dice are essentially a 75% chance to cause 1 hit compared to the 50% chance for blue dice). A 50% chance of a hit on 25% of the dice results is a bonus 1/8 chance.

Therefore, the card effectively reads:

"When attacking a squadron at close range, blue dice have a 5/8 chance of causing a hit rather than a 4/8 chance."

On a ship with two anti-squadron dice, Point Defense Reroute essentially adds 1/4 average damage within close range. It costs 5 points.

Upgrading Neb-B Support to a Neb-B Escort or a Gladiator I to a Gladiator II costs six points, adds 1/2 average damage out to medium range, and has other benefits besides.

I could see taking it if it just straight up allowed rerolls of any anti-squadron dice within close range, but as printed it is not worth taking on any ship rolling less than four anti-squadron dice. I don't believe we'll see any ships with more than two anti-squadron dice as I think they made a concious decision during game design to disallow ships from one-shotting squadrons without special circumstances such as Concentrate Fire or Dominator. The card probably originally turned crits into hits, and then they changed it in playtesting once they decided Wave Two would have black anti-squadron dice.

You're not factoring in everything well.

Fighters attacking you will be in clise range. It helps you defend you.

Beyond that it adds about a 13% chance to hit per dice. That isn't bad.

I do agree, it's mediocre. But if you're running no fighters it can offer some level of extra protection. If you're running fighters, which you always should be, then it is in fact worthless.

Dice may be re-rolled multiple times. I'm not sure if this card is meant to allow you to do that (most effects can only be used once per relevant trigger), but it's wording is open enough it's worth asking for a FAQ. If so, it changes 4/8 to 4/6! If not, it's still only 5 points, and you can catch multiple squadrons in a single firing arc.

Edit: Somebody else had this question a couple of days ago, looks like it does not re-roll multiple times.

https://community.fantasyflightgames.com/index.php?/topic/176133-point-defense-reroute/

Only ship that may get benefit out of it (in my opinion) is the Ass Frig IIa. But even then you would have to catch 7 TIE's with AA fire to break even points wise on average.

I suppose it may have benefit by increasing the chances of getting 3 points of damage over 2 turns to shoot ties down with, but really this is one card in wave 1 that I will probably never use. Compare it to expanded hangars (also 5 points) and it really falls apart.

Maybe if it was 2 or 3 points?

It'd be worth it if it was 2 points or if it was "May reroll crit, blank, or accuracy". As it stands I'd rather just spend the points on an Escort refit and interlock fire from multiple sources to kill squadrons.