As Zarkkast said Thunderlord's Decree isn't nearly as bad as DFG, but I can see why you'd think the additional burst causes gameplay health issues, not unlike DFG.
got nerfed because of TLD; she could proc it with just her ult, and her E->R combo literally chunked more than half of a squishy's health because of TLD. Not to mention her Q and E, both can count as "double-hits" for the proc, which gave her laning a significant boost. TLD by itself caused gameplay health issues for her. Granted she was tweaked during the mage update, but still...
Part of the reason
is so annoying is because her plant's act as TLD proccer's, which makes her bullying even better. And her trading as well. Q-W-plant-> TLD proc and you've chunked your opponent for quite a bit. Zyra's power is elevated, and thus could become reliant on, TLD, just like how some mages **(
) **became reliant on DFG.
Those are just two examples that came to mind, but there's probably more.
TL;DR: I agree with OP that TLD causes gameplay health issues like DFG, albeit on a smaller scale.