Meh... it's not as if an opponent will often want to fling it back. It might cause you to lose damage races once in a while, but the drawback isn't in the same league of Flame Rift or Fork. The problem is that 3-for-2 isn't good in the first place.
An anology: Some horrible Shahrazad milling decks can appear vicious unless you realise that you don't have to play along - concede subgames, suck up the life loss and they fall apart.
In both cases the opponent can completely avoid the uniqueness of the card. The difference is that if they do so, Shahrazad provides a strong effect (1w for half the opponent's life) that doesn't work well with the rest of the deck while a vanilla Chain of Plasma is weak all-around.
Giving an opponent a choice only works if it's a 'damned if you do, damned if you don't'. That is arguably the case with Browbeat - 5 damage or 3 cards are both very good returns for 3 mana (personally, I still don't like the card). An instant Volcanic Hammer is nothing to write home about.
In theory, a situation might come up where Chain of Plasma does something that doesn't require the consent of the opponent. We can't pave the way for this though, because possible synergistic cards (such as Fiery Temper) are too weak to run in our own deck.
There might be bizarre applications such as massive self-harm in the face of a Pulse of the Fields, but those occasions will be too rare to be significant.
