No where in either of those does this hint that a green, pulsing, glowing circle of light should shine under the target's feet.For example I would point out the spell Freedom of Movement. According to the NWN Wiki the spell description in game for this spell is as follows: The target creature becomes immune to paralysis, slow, and entanglement spells and effects.
According to d20 SRD the spell Freedom of movement has the following description: This spell enables you or a creature you touch to move and attack normally for the duration of the spell, even under the influence of magic that usually impedes movement, such as paralysis, solid fog, slow, and web. The subject automatically succeeds on any grapple check made to resist a grapple attempt, as well as on grapple checks or Escape Artist checks made to escape a grapple or a pin.The spell also allows the subject to move and attack normally while underwater, even with slashing weapons such as axes and swords or with bludgeoning weapons such as flails, hammers, and maces, provided that the weapon is wielded in the hand rather than hurled. The freedom of movement spell does not, however, allow water breathing.
Another point I would bring up to this is the following. Arelith has taken the steps to obfuscate the character description box to make sure that you cannot see a list of applied effects to that character by using examine. This means that if I were to examine a creature (PC / NPC / Monster) I would have no way of knowing that the target was under effects like any animal buff, or haste, or even mage armor... but I can tell that they have Freedom of Movement, Premonition (which has the description that the caster is able to see into the future and avoid damage), Protection from Spells, or Spell Resistance (the spell), and even Protection from Elements (or any of those other elemental protections spells), simply because of persistent visual effects.
If left up to me I would suggest that many of those immersion breaking spell effects that have no valid reason for being there be removed. This would, for me, improve immersion as well as help with GPU and Frame Rate performance (especially in larger events), as well as leave a bit of doubt and mystery when confronting another player or NPC - having some question or doubt as to what buffs (if any) they might have on them. All of these are, I think, good arguments for removing these visual effects. I can't really think of a good reason for keeping them except for the more obvious spells that should have them like perhaps Barkskin which does not explicitly say that it makes you look like a piece of wood, but does say that it toughens your skin.