Forger101's post was in order to gather ideas on how we could improve trash in order to make them more interesting. As HousePet pointed out, adjusting monster density in zones to account for packs isn't hard.
But pack mobs and kill the player harder isn't the only way to get the player to take notice of mobs. The update to plants that let them spit poison hasn't contributed to any deaths for me personally, but I'm much less inclined now to ignore them outright.
Rather than poo pooing his idea, can we try to contribute? In the end only one person needs to be convinced of rather or not implementing these changes is a good idea.
For my own part...
Worm Masses merging into more difficult monsters if X other Worm Masses are nearby sounds good. It creates pressure and doesn't require good AoE skills to deal with but rather priority targeting.
Map Effects, rather on move or on death are something else we haven't used a lot. These can really change priority targeting as well. Killing a mold that explodes in a cloud of poison gas isn't something you want to do when fighting a bunch of other mobs... or is it?
Rats (and wolves) are probably my two biggest pet peeves right now. Rats aren't something that strikes fear into my heart. But a swarm of rats that have some kind of grapple like effect is scary. Disease carrying rats can be scary too. Perhaps some kind of combination of the two. Maybe only when X rats are adjacent to the player can they swarm. Again, priority targeting makes the player *think*. ToME bills itself as a tactical RPG. Making the player consider how they approach even trash mobs is good and it doesn't have to be done by adding attack, defense, and damage.
I also liked the psychic rat swarms in the D&D planescape setting. These had a group mind and would be stronger the more of them that were around. Again we have a mob that can work better in groups forcing the player to think about who their next target is. Do you kill the bear that's mauling you? Or kill a single rat so the swarm stops spamming Mind Sear?
Please let's contribute. Even if Darkgod says, nah, starting zones are tought enough. Maybe we can implement some of these ideas in new monsters or new campaigns There's no harm in brainstorming
