Some of the players at least argued that a) comparatively few ranged touch spells exist, b) spellcasters don't have calldown, so they have to gamble that their prepped spells will even be used in any adventure, c) three of the players are very smart, experienced, and clever and thus know how to use their shit, and d) the module he is trying to integrate into the larger campaign is really too low-level for the party, and he should be substituting tougher monsters to challenge us more.
Personally, I think that the problem lies with the DM: he's not used to having monsters as main opponents (his usual Forgotten Realms involves the PCs fighting the Zhentarim), and he is very lenient with what prestige classes, feats, and spells he allows- his philosophy is if it's in a WotC book, it's fair game. I think all of these factors are more to blame than ranged touch attacks.
What do those of you who have played 3.0/3.5 think? Are ranged touch attacks overpowered?