I wouldn't mind if grey elves and high elves became one race, they don't differ too much indeed.
I disagree about spellcasters being very much like one another. Yes, priests and wizards don't differ too much, the priests' detect item status ability is the biggest difference. But elementalists are very different, look at their class powers: immunities, breathe water even, some special spells and walk through stone (like a monk). But the damage rolls on their spells are different, really (I think they increase when you lvl-up). Never experienced with a lvl 1 elementalist you had to scorch a large bat twice before it died? But when you're lvl 10 you can scorch them in one go pretty easily. I don't think they're that bad, you get spells for free and their main spells work well enough on most enemies.
And necromancers are summoners, for the creator's sake! If too many play them as pure spellcaster, maybe their spellcasting powers should be decreased somewhat. But there is always a good use for summoning powers even if you play as spellcaster, so I don't think playing necro's as pure spellcasters is smart. Druids are quite different again, mostly because animals just don't get hostile (exception of vaults and tension rooms).