What Sharauvyn said +100. It would be one thing if you COULD actually control your familiar/animal companion with any sort of regularity, but...it just doesn't happen. Thats the truth, pure and simple. A couple other point as well...
Its one thing for my Wizard's familiar to have to be Raised on death. Its another thing entirely for my Druid's (or a Ranger's) Animal Companion to have to be Raised. For starters, the Familiar is a lot better at taking damage from the standpoint of the buffs the Wizard has access too. If I cast Mage Armor, Cat's Grace, Endurance, Bull's Strength, Stoneskin, Pro. from Evil, GMW, Flame Weapon, and Improved Invis on my Familiar, and then Haste it, it STILL dies in any REAL fight. It's AC is still too low, it has only 5+Con HP per level, and no real abilities to speak of, essentially having a shortsword (1d6) +3 +1d4 fire damage. Hell, sometimes I even waste potions on it just to make it a TINY bit better (Barkskin and the like). Now, compare that to a Druid's companion...who will be lucky to get Barkskin, Bull's, Stoneskin, and GMF. Awaken at higher levels...still not even close to comparable. Not EVEN CLOSE. And the Ranger? Their Companion will get Cats and GMF. Thats IT. PLUS no Summons to back them up. Good luck with that. But they still pay the same cost for their Companion dying? Did the Ranger and Druid classes suddenly need ANOTHER nerf?
And, as for the RP aspect, sure, thats great...but thats not what Familiars are for in NWN, unlike PNP. If I am with a group, I don't even SUMMON my Familiar...not enough spell slots to go around, and, being inherently uncontrollable, they do nothing but screw things up in most situations. Since it isn't there, so much for RP. It only comes along when I am either alone, and need it, or with one or maybe two other people. I use it occasionally for window dressing, but people get so snippy most of the time if you take it ANYWHERE near civilization, its ridiculous. And its not even like we are talking about a Demon or Devil or anything...its just a big wolf. Which, granted, I can see the Barovians being deathly afraid of...but other PC's? Really?
Overall, from a purely mechanical point of view, I could care less if my Wizard has to raise her Familiar once in a while...but this is pathetically unfair to those with Animal Companions.