Actually I think it was changed to cost more lava recently. I see that it takes 50mb at a time now instead of 10mb at a time from before. However thats all relative when you have basically infinite lava coming in. But really a lot of power generators can make power automatically easily. Some are more fun then others of course. Really any generator that can use charcoal can easily be a set and forget since a simple tree farm can feed it. Its really up to the player themselves on how much fun they want to make it. If they want to go the boring lava route and pump it and forget it, thats up to them. Charcoal farm to Steam generators, ok fine, its a little more involved and bigger build. Witch farm feeding the new dynamo's or heated redstone generators. Enderman for the ender generators. Even if they want to be "eco-friendly" and use solar's ok fine.I feel as though it should have a lower power output or a higher consumption rate of lava. But honestly, it's balanced for TE, not other mods. It works well with the intended progression of TE, and that's all that they were going for.
Plus several mods have started to put configs for server owners to nerf/buff things as they see fit. Its really pointness to nerf the magmatic cause then some other form will be the new easy boring way. Its up to the player on how easy/hard they want to make the game to provide the most fun and unique builds.