Thats something I hate about almost every Hack'n'slash, if I am getting stomped by one thing its a huge hassle to go stockpile items for the one resistance I need. In fact in the process of running around looking for crap I usually level up enough to make it an non-issue. Happens a lot in Titan Quest, thats why like to use the Vault program. If I need extra cold resistance I just hop into the Vault and find items I already got on another character a long time ago. Easy.
Real role-playing games are usually easier cuz I know what I need and exactly where to find it. In Baldurs Gate 2 there is a need to resist Imprisonment at key points in the game. But I know where those points are and exactly how to deal with Imprisonment, so its not a major headache.