True, but if you just get Ethereal Blooms you can get rid of the taint without having to deal with those monsters. Granted, the game probably wouldn't give warning about this, I definitely didn't find out that you could get mind spiders from warp until it happened. So I guess leaving it as a pure warp effect would work fine, but I feel like if possible making the most powerful stuff from other mods give warp would still be a nice feature. I find myself shying away from using Void Metal because of all the warp, and instead get myself Terrasteel. If they all gave warp, there wouldn't be any reason to use one over the other and the game would be equally rewarding no matter which path you take.
How would the warp effect take place? Would it just spawn in Tainticles around you? I feel like it would be cool if, without notifying the player, it tainted a section of the land around them (this wouldn't do much until late game when you've already cleaned up a lot of the land but if you don't notice you might have an entire continent of taint to clean up again). Another effect could be the game giving the player a message "You hear a buzzing from somewhere, almost like a beehive..." and then spawning in a few Taint Spore Swarmers around the player. Or how about one that drops a whole bunch of Taint Spores like bombs from the sky so you have to deal with Taint Crawlers? I don't know, just thinking here.