I wouldn't mind a system that let me type /floor # in Arcadia, spawned me on that floor with a random assortment of equipment, spells, skills and talents and created a test save file of that point. That way I could just keep hitting that command over and over, running through that floor or the ones past it and do ridiculous things trying to break the game.
The random equipment/spells/skills/talents would be helpful in sniffing out strange causes of crashes, since it'd give me a reason to use things I normally ignore.
I can't imagine it'd be abused if it awarded nothing to overall score or essence count.
I was kind of hoping it would take a bigger hit from the removal of its slow, which I thought was one of the reasons people managed to survive with it. I'm a bit too tired to think right now... but the Fireball doesn't feel nearly as overpowered, does it? In theory you can run around and kite with that, too, but for some reason it seems to fare much worse than Insect Swarm.
Perhaps a way to stifle too lame tactics would be a "timer of death" that activates when you're way below C rank in time, starting to spawn invincible thorns or something... but that's a scary road!
People didn't spam it because it slowed enemies, but because it requires very little targeting and does a lot of damage over time.
Fireball requires aiming, insects have some wiggle room in where they can hone in on enemies. Fireball puffs out after one hit, insects linger and can switch over to other enemies after they get a kill.
If a skill just requires you run along the outside of the stage and tap the button every so often, it's a little broken.
Spirit Slash at least requires you be near enough to your enemies to potentially be hit by them.
I could think up a few quick ways to balance insect swarm, possibly.
1) It behaves like a summon. When one swarm is out, the EP required to cast it is blocked and doesn't unblock until every insect in that swarm is dead. Doesn't stop circlestrafe-spamming, but it would slow it down considerably. Not sure if this is a good idea.
2) Similar to 1, but every insect summoned acts like an EP blocker. As each individual insect dies your EP is unblocked. Still not sure if it's a good idea.
3) If you move too far away from the insects, they immediately die. No more spraying and running endlessly. If you move too far away from Snowman, he flees back to you. Same with Cloud Buddy. There's consistency in applying some sort of proximity requirement to the insects. I kind of like this one, requires that I actually have to get near my targets somewhat.
4) Every time you cast insect swarm you have a brief Movement Speed debuff applied to you, temporarily weakening you somehow? Would make spraying and running a lot harder.
5) Make Insect Swarm a TRUE spray-and-run-away spell. If the enemy they're targeting dies and you're the next nearest target, they'll turn on you and fly after you instead, draining your HP like Bat Swarm does.
Any one of those would make it not quite so skill-less. You've got people who were struggling with beating Flying Fortress sailing all the way through Seasonne using just this skill, it's far superior to Shadow Clone which actually requires constant enemy proximity and danger of being hit.