(sorry for longish post)
Honestly for def, I think the stat doesn't mean much anymore, and that's ok. For instance, fighters get 25% damage reduction from tactics, additional damage reduction from equipping a shield, and tons of hp from a high strength build. This is before adding features like tanking stance or shield bash (which can now cause bleeding). Rogues with GM foils can hold out quite nicely against melee mobs with parry, dodge, and gouge. Monks get mirror images, throat strike, and yeti aspect. I'm seeing def relying less on a single number, and more on a character's skill set, so instead of focusing on increasing the importance of def, we should focus on increasing the threat of melee mobs.
At low levels, fighting melee mobs was actually interesting. Probably my most memorable EUO moment is still stealthing past golems in VOTs (and finding a shadow warrior for the first time was pretty terrifying). They were fast, hit hard, and the only way I could escape was by outrunning them and hiding. Anyways, I'm just going to throw out a bunch of completely random thoughts I had on melee mobs based on that:
- increase melee damage (pretty obvious)
- put them in narrower rooms, or a labyrinth with dead ends, so you can't run forever.
- mobs glow (or show some sign) when close to 100 rage, so combat with them is more intimidating. Maybe give the player one or two seconds to realize what's happening, since when I get killed by a sudden flurry, I'm usually just annoyed, because there wasn't any build up to the attack. I think this would make combat with melee mobs more dynamic.
- give more of them the capability to cast reveal. Melee monsters are too easily shut down by invis at high levels.
- earthquake ability that can 'trip' you, hamstringing or slowing you until you get up again.
- Have melee attacks be faster, at least for some mobs. Since melee attacks aren't as flashy as spells, I think melee mobs would be more interesting if they hit faster, so you'd hear lots of damage noises and have your screen fill with combat messages.
- hamstring chance with hits? (not charge, because I think it looks a little cheesy, but just a chance to hamstring on a hit. Shouldn't be too long though)
- charge (but shorten the range so it doesn't look ridiculous when they miss)
- slowness chance? (maybe like 1 or 2 seconds)