Indeed that is a fair concern and a valid point. As to whether or not it is a punishment or janky is debatable, however.
One perspective is that a high investment into a skill class should be guaranteed positives, and labels the suggestions as negatives due to an aversion to environmental risk. Another perspective suggests that environmental mechanics are inherently neutral and can be both positive and negative, though I would add a caveat to exclude Deathfog as there is no way to use it to one's advantage in any scenario (at least that I've seen).
I subscribe to the latter, and suggest that familiarity with mechanics and proper preparation and group composition mitigate at least some of the inherent risk surrounding abilities with friendly fire potential. The smaller the party, the less relevant this becomes, and the more likely one would devote this many points to a single class.
However, objectively-speaking, the degree to which we vary in our opinions of the dangers of environmental damage is not the subject of the thread. The only difference between my suggestion and standard skills is that it requires a heavy investment into the skill class. I agree that this is a logical justification for exploring an alternate suggestion, however I do not see any alternate suggestions. I like the OP's suggestion, but what are some other rank-10 Pyro bonuses that may be appropriate?