Since Ferocious Bite refreshes Rip when used on a target with less then 25% health, it would be nice to have this spell light up when your current target is below 25% health.

There is more to consider here: is Rip running off and how would it be refreshed - with the number of combo points from the previous application or with the combo points spent on Ferocious Bite - speak is it worth to cast Ferocious Bite with less than 5 combo points just to refresh Rip? Also normally Rip will flash when the player has 5 combo points, which could then be misleading if Rip is up on a target with less than 25% health.

I would be happy if you could just make Ferocious Bite light up when the enemy target is below 25% hp. I'll track the RIP duration myself.
And to answer your question: Yes you can refresh rip with a 1 combo point Ferocious Bite, and it will still be at full power.

Add the following as a custom rule for your druid:

return Configure {
    "Feral Ferocious Bite",
    format(
        "%s when %s is below 25%%.",
        DescribeHighlight("flash"),
        DescribeAllTokens("enemy")
    ),
    22568, -- Ferocious Bite
    "enemy",
    { "UNIT_HEALTH_FREQUENT", "UNIT_MAXHEALTH" },
    function(units, model)
        local foe = units.enemy
        if UnitHealth(foe) / UnitHealthMax(foe) <= 0.25 then
            model.highlight = "flash"
        end
    end,
    1079, -- Rip (feral only)
}

I don't feel this should be in the standard package, but if someone feels another way, please issue a PR.

It should also check for Rip on the target, at least.

We could have a second addon with "helper" rules (by opposition to the "informational" rules) that could be disabled all at once.

Also, since there is at least two ways to upgrade "hint" to "flash", I think we should restraint from using "flash" in standard rules.

@ Rainrider That works great man, thanks