One of the problems that devs seem to fall into in this stage in the history of gaming, is being too worried to create OP items that are fun. All items don't HAVE to be balanced in a single player game. Anyone who has played BG2 has seen some perfect examples of downright broken items that are completely fine, because its single player. Non-detection cloaks that mean your stealthed champions can never be detected. Broken. Fine. Fun! DOS 2 doesn't have to settle for basic and bland effects on their gear. Its not a moba where balance is EVERYTHING. There is no reason why broken effects cannot be used. You might not want to include them in the arena mode, but there is SO much scope to have fun with item designs. What would be wrong with including items that have 100% chance to add an effect like bleed or slow? I completely agree with the OP, why not completely change up items and make them fun?
For example
Shield: Immunity to all disabling CC. Broken. Fun. Completely okay in a single player game. (even a 50% chance would be alright)
....
It doesn't matter that these effects aren't balanced, because they are fun and they add to the experience. To combat the strength of these sorts of effects, you can up the difficulty of the mobs you face. If anyone has a well reasoned argument as to why these sorts of effects should not be added, I'd love to hear it. What does the community think of adding items such as these?
I agree that fun is overall more important than perfect balance, but I don't think balance needs to be ditched to make really fun, wacky or off the wall items. I don't want to feel like an item is really fun and cool, but broken so I won't use it if I want a challenge. I think we could have a mace with something like "Each strike knocks enemies back by 1m," which (assuming it's not a pain to code well), would be goofy and fun and create totally new strategies but wouldn't be completely broken.
By fun, I think: will this change the way I play in a significant, interesting way? Are there multiple ways this item could be used? Personally, I don't think something like an insta-kill 10% of the time would be fun. I would just use that item as I normally do, but sometimes kill enemies instantly. If, instead, it was something like, "When below 10% health, this weapon automatically crits," it would be fun and might make you play more aggressively to get the bonus and then cautiously to take advantage of it. Balance and fun aren't mutually exclusive, and in fact, can complement each other.