It just won't block DOT. I remember playing with the High Elf and when using Expulse Magic it negates meteor shower CAs on dragons in the Carnach Caves, for instance, so Area of Effect CAs are covered. Hence my question because if a boss fight takes more than 45 seconds then you might be in more serious problems than with its CAs being (mostly) blocked. For mobs you can just run off for those 15 seconds and get back, and if the build is made sturdier with added defensive skills then it's easier to leave out alive I guess.
I'll confess to have reinstalled the game and the D2F mod. I've had my first long night due to that, having started a Paladin and playing it by ear without planning it to the inch. It's refreshing to actually play a build without planning every aspect of it. Sure your diary gave me the main idea for it, but I'm choosing the skills and modifications on the go without having them written on a Notepad file like I always did. It's feeling good right now. Love the new mobs I've encountered so far, the Putrid Defilers were such a surprise to me! I've installed the music pack and I'm playing D2F+SS+IM in Easy and so far I've found it very manageable with Holy Fire+Prayer, but it's really like playing a new game. Sure the game world is the same as always but it does feel different, so job well done! I've been concentrating on modifying my CAs since I use so little of them but eventually I'll have to turn into Normal difficulty and start doing more than running around killing mobs.
I've noticed an incongruity between Holy Shield in-game and on the Wiki page. The tooltip for the Boost mode in-game says the reduction is 20% but the Wiki states 25%, so I guess the tooltip is wrong?!