If you change the BODY value of a player his stats like ARMOR and DAM will be set to the body chardef which is a VERY undesirable behavior, specially when using the Necromancy spells effects and other changing body spells.

So my suggestion is a) make the change to body only an esthetics change (which I find the best way) or make DISPID a changeable value on mobiles (players and npcs) which doesn't have the counterpart of changing BODY, meaning, it's an esthetics only change.

Some of us consider this very desirable behavoir. Makes a shapeshifting script less work. Sure maybe just adjusting armor and damage wouldn't be hard, but food type, body flags all this is handled automatically which is very convient for most people. Especially since there isn't another way to change a lot of this stuff... and having only the staff you can't override on a player by player basis like body flags change without the other stuff changing would be weird. Option A would be a huge pain to everyone who is used to the default system so it would not be the best way at all.

This DISPID solution might work. But then we have 3 "bodies" for each mobile, the one being shown (DispID), the one stats are derrived with(Body), and the default body the player will res as (Obody).

If adding a DISPID can't be done, maybe make this an .ini option to determine how to handle it, like armor stacking.

I don't think allowing DISPID would be so hard, it's just a matter of what image to send to other clients near you.
Maybe also a tag like .TAG.IDTOSHOW.
And indeed I think now DISPID solution would be the best way, since it wouldn't break people that use the old way. But still, spells that shapeshift (necromancy and ninjitsu for instance) can't be done correctly with the current behavior, unless that addition is made, same for Polymorph which doesn't work like on default UO.
Other things like special abilities of Champions, like Barracoon, or the peerless Travesty also can't be done.

So my suggestion is to make a esthetics only thing and keep everything else as the original CHARDEF (can flags, armor, damage, etc).
For example, on OSI if you use Lich Form you keep your stuff equipped, the only difference is that people will SEE you as a Lich (and of course the other special stuff like mana regen and health degen).

Any plans on doing that?
Cause, for some reason (bad thinking before doing i'd guess), players are only considered players when they are humans or elfs, so a polymorphed (or with the new necro spells, changed to other bodies), thus they can't buy and do lots of stuff because the CHARDEF of their current body doesn't allow (but I also don't want to allow the npcs to do what players should be doing, for example equiping), also TEVENTS go to the player too, amazing =D

Another thing is the notoriety. If I'm in a human/elf body, the PlayerEvil and PlayerNeutral settings are considered, if not they are not.

So, c'mon, do I have to point anything else?

+1 to changeable dispid, then people using body to alter character status won't be troubled and the new tweak to DISPID will allow others to only change body display

+1

+1 for the dispid, it would really help to get rid of a lot of trouble using race and polymorph systems.