pawsplay said:
Really? As a DM, I am no under no obligation to allow such a character in the first place. Heck, I might not even have Necropolitans, and if I do, they may not be 5000 years old. Second, even if I do, it's up to me to say whether they've actually seen everything.
Let me put it this way. You have a Wizard and a Sorcorer in your party.
The Wizard is an elf who's on a quest because she lost her memories and fell in love with her brother who was then being cursed by her childhood friend because she really liked the guy and thought the whole thing was creepy but didn't realize they didn't know what was going on and turn him into asome sort of wacky creature. Now the Wizard's on quest to find him and the only hint she has as to what he's turned into is a riddle which I don't feel like trying to make up. She has been doing this for the entirity of her very long life and has a legitimate reason to have personally seen and studied 99% of creatures which exist in your campaign world. She also has the Knowledge skills to back this up.
The Sorcorer is a young Lord of incredible innate power who's never been out of his castle before in his life, and but on the day of his coronation, it turns out he's not actually the heir, he's a changeling swapped in by the fae, so now he's decided to find the real heir to take his place before the neighboring nobles mustle in while there's no real leader. He has no idea where he's going and is wandering around getting hoodwinked out of his large amounts of money before latching onto these "adventurers" (who seem like some sort of travelling sideshow).
Both have interesting backstories. Both are fine characters. If both have Polymorph, the Wizard can turn into anything, the Sorcorer can turn into a horse or a dog, maybe a cow. They're getting combat bonuses/penalties based on their backstory, which (unless it's volantary) is Bad Game Design TM.
It's merely "not very good" as a house rule because the GM can be aware of it and balance it out with appropriate bonuses, but a game designer can't, so it's seriously bad from that perspective.
pawsplay said:
Third, it's up to me to decide what there is to see. If there are no War Trolls in my campaign, you can't have seen one to polymorph into them. One of my players asked me what they can use; I said, "Anything in the MM, and anything else you can justify to me."
And that's fine, in fact that's what I was doing before another GM in our group just went and hit it with the ban stick.
pawsplay said:
Let's say I do allow anything, anywhere, uncritically. So what? Fundamentally, we're talking about a natural AC boost, some reach, some natural attacks, and some movement modes. There are other spells with vastly more significant effects.
Thing is, I'm pretty sure there are no other spells which give you access to all of those things, which let you choose between all of those things at casting time, which let you choose between turning into creatures tougher than the Fighter (or even just arc the Fighter that much more), or gain any movement type, or gain acces to specific attack types (like grapple or bull rush as appropriate). It's the open ended-ness which is the problem, both in power, and in slowdown.
Of course, even with this, many groups won't have a problem it's just that it tends to slow down play, overly encourages silly types of system mastery, and puts restrictions on monster design that don't need to be there. All of which means it's just better off working like PHB2 shapechange or summon astral construct.