Mobs tend to not be very effective in 3.5
As you noted, the orcs were torn to shreds. The party had powerful, area-affecting debuffs available, and used them. Meanwhile, due to the extreme degree to which the orcs outnumbered the PCs (5:1), we expect that the orcs were commensurately low-level (the CR guidelines would suggest that their numbers alone represent a CR increase of about +8, which means even if these were 1st-level orcs, the CR guidelines consider this a CR 9 encounter).
The issue is that 1st-level characters are going to have a very hard time saving against 6th-level characters’ save DCs, and a very difficult time hitting 6th-level characters’ AC. At 6th-level, the druid could easily have gotten some quality non-metal armor, the fighter would probably be in full-plate or magic armor, and even the sorcerer might have a mithral buckler and mage armor already up before the fight began. The spellcasters have 3rd-level spells available, and should have +2 to their primary casting ability, which means their DCs have been improved by +2 to +3 relative to their 1st level selves. And 1st-level orc warriors aren’t exactly noted for their saving throws in the first place.
So in a lot of ways, you don’t want to use encounters this large. They rarely pose significant threats, and they cause major headaches at run-time. Rather than being “medium-sized,” this is “quite large!”
That said, there are management options available
Especially if you are mapping out encounters. For example, there are “condition markers” available for sale, or that you can make yourself. For example, this guide shows you how to make these:
Just stick them under your miniature to indicate statuses it’s got. Or just use colored pieces of paper, like Post-Its: if you rotate them slightly with respect to one another, the corners will stick out so you can see each color (and Post-Its will stick to each other to maintain that orientation). Just about every virtual tabletop software also has similar markers to indicate status, usually little icons put in the corners of the creature’s token.
If playing “theater of the mind,” what I have usually done is simply kept track of the numbers of affected/unaffected targets, and the actual HP ratios generally just for one enemy per character: the one that character is fighting. My players tend to focus-down enemies (which tends to be an optimal strategy), so I don’t really need to worry about what’s happening to other characters. My players just say “OK, I’ going to attack one of the blinded ones,” and I note that they’re in combat with a blind one. If unblinded ones come to attack him, I note he’s in combat with one blind one and a couple of unblinded ones, and he’s hurting the blind one. If he kills the blind one, I just note that there is one fewer blind one.
Obviously, sometimes I have to get a little more detailed, such as if he leaves the blind one half-dead because the unblind ones attack and he switches to them. It happens, but basically until it does (that is, until a player singles one out), I just treat them as part of the generic group of unblind ones and that’s it.
