I would take it OUT, no question.
Some assumptions: first, classes are fairly well balanced, and that balance assumes SR is the exception, rather than the rule. Second, each class has an area where it excels, and other areas where it's abilities overlap with other classes.
For arcane casters the area of specalization is offensive spells that directly harm their foes. Check the spell selection of virtually any arcane caster and you will see that at least half of their spells are offensive. Sleep and Fireball are the bread and butter of arcane casters. IF the majority of enemies have SR, then that offensive power is significantly reduced.
Sure, an arcane caster has other spells available, but they share most of these spells with divine casters. If you are going to have a similar spell sellection the benefits of playing a cleric become overwhelming. I would expect arcane magic to be a big part of any drow campaign, but if you leave SR in then either players will not want to be arcanists, or those that do will be forced into the support role of clerics.
You can argue that SR is what makes Drow, Drow. I think there is a stronger argument that offensive spells are what make wizards, wizards. If you are going to be reduced to casting magic weapon, bull's strength, and summon monster your not a wizard - you're a cleric with crappy hit points, no healing, and an AC 10.
Moreover, I think Drow having SR is more of a historical accident than an intrinsic part of their character. Drow first appeared in a high level 1st ed. adventure. SR (Magic resistance in that edition) was necessary to keep them from being pushovers for fireballs and similar spells. Likewise faire fire (a ridiciouls power if ever there was one) was to prevent invisible characters from walking all over them. While later editions have make wholesale changes in many areas of the rules, many iconic monsters are stuck with powers that seemed like a good idea in 1979, but should have been taken out long ago (don't get me started on demons teleporting without error at will and summoning other demons).
In short, I think you need to decide which is more important for a drow campaing, SR or arcane spellcasters.
Some assumptions: first, classes are fairly well balanced, and that balance assumes SR is the exception, rather than the rule. Second, each class has an area where it excels, and other areas where it's abilities overlap with other classes.
For arcane casters the area of specalization is offensive spells that directly harm their foes. Check the spell selection of virtually any arcane caster and you will see that at least half of their spells are offensive. Sleep and Fireball are the bread and butter of arcane casters. IF the majority of enemies have SR, then that offensive power is significantly reduced.
Sure, an arcane caster has other spells available, but they share most of these spells with divine casters. If you are going to have a similar spell sellection the benefits of playing a cleric become overwhelming. I would expect arcane magic to be a big part of any drow campaign, but if you leave SR in then either players will not want to be arcanists, or those that do will be forced into the support role of clerics.
You can argue that SR is what makes Drow, Drow. I think there is a stronger argument that offensive spells are what make wizards, wizards. If you are going to be reduced to casting magic weapon, bull's strength, and summon monster your not a wizard - you're a cleric with crappy hit points, no healing, and an AC 10.
Moreover, I think Drow having SR is more of a historical accident than an intrinsic part of their character. Drow first appeared in a high level 1st ed. adventure. SR (Magic resistance in that edition) was necessary to keep them from being pushovers for fireballs and similar spells. Likewise faire fire (a ridiciouls power if ever there was one) was to prevent invisible characters from walking all over them. While later editions have make wholesale changes in many areas of the rules, many iconic monsters are stuck with powers that seemed like a good idea in 1979, but should have been taken out long ago (don't get me started on demons teleporting without error at will and summoning other demons).
In short, I think you need to decide which is more important for a drow campaing, SR or arcane spellcasters.