That sounds promising. I've been maining Zyra (both mid and sup) since Season 3 when I started playing. Her kit has been pretty stagnant since the nerfs as a result of her popularity as a support in Season 3 Worlds.
One of the main problems is 'mobility creep'. I remember doing very well previously in the Zyra vs Ahri match-up pre-6, but as soon as she gained her Q MS buff in early 2015, the match-up immediately worsened. And later that year when Ekko was released, having a dash which leads into a blink, and a massive 'f**k you' teleport to safety ult felt terrible to play against. Those are just two examples of many. This is compounded by the fact that everything in Zyra's kit has a noticeable delay: passive 2s delay before you can fire, Q delay, R damage and knockup delays (1 and 2s respectively).
In my opinion, Zyra is pretty good right now, the plant AI improvement a few months ago helped a little, and the introduction of Thunderlord's has really enhanced her poking/burst patterns, which I hope will be preserved. Her EWQWR combo nuking multiple targets, with plants providing constant dps/slows is basically the high-point of playing Zyra. I won't be sad to see her passive go, it's rarely useful and very unreliable.
It would be ideal if both of her playstyles could be preserved but I would prefer for mid to be prioritized over support. I just hope we don't end up with Zyra support becoming massively popular again and as a result mid Zyra gets trashed. The problem with balancing Zyra for both roles has always been that what has makes her a strong mid also makes her a strong support - you can't effectively nerf one without nerfing the other.