Recent returnee to Homecoming, I used to play a 50 Plant/Psi Dominator back in the day (pre Going Rogue) and, of course, I've remade the character and been replaying through the game, and while I recognized the Spirit Tree change as new, I hadn't realized Seeds of Confusion had been nerfed. Carrion Creepers were also, without a doubt, my single most favorite power out of the set, and I just recently regained 22 to get them. Since this topic is near and dear to my heart, I thought I'd give my thoughts, understanding that criticism is meant to improve things.
I have several builds I've played with that felt overpowered, such as a Dark/Dark tank, where it feels like you can charge into a vast group of bad guys and rampage through them feeling invincible. My Plant/Psi Dom felt like that, especially in the later levels, back in the day. He still feels like that. I don't feel particularly nerfed.
Seeds had felt very short to be and I hadn't realized it was nerfed but it makes sense, but even with the nerf it still feels like an essential tool of the set. Throughout my build up in early levels, it remained my opening move. With three Confuse SOs in Seeds, by the time the enemy frees themselves from confusion, it's usually recharged. I do struggle to Confuse Bosses with it though (I really appreciate the option to fight bosses when solo, BTW). Perhaps that's part of the nerf?
I used Spirit Tree back in the day, but it was more of an emergency power. I often found I had to carry teams during bad pulls or when we underestimated how bad a boss was, and Spirit Tree was a great way to keep everyone fighting fit, but it was a back pocket sort of power, something nice to have in an emergency. It still feels like that, but acting as a tank is a nice little bonus.
I've just tried Carrion Creepers and it seems fine? I went rampaging into a large open world spawn and pulled a few more spawns in and the Carrion Creepers did fine? Better than I expected given that I just got them and they're not even slotted yet. Carrion also felt like an emergency power, but a tac nuke when used properly, It still feels like that, so far, tentatively, with the one use I've seen so far. But it behaved like I expected it to. The real test would be what I used to do in... Grandville? Or the PVP area for 50s near Grandville, which had huge spawns that I'd go drop carrion creepers and see a dozen tentacles spring up and total chaos unleashed. What I pulled just now was smaller than those near armies, but seemed similar in performance. To me, Carrion Creepers filled a similar niche as Ice Patch did for Ice Controllers, except way more fun: just creating a generally chaotic environment into which you could apply some spot control. It still does that.
I won't be sure if he behaves appropriately at 50 until he's at 50, but so far my experience with him has matched my expectations. The nerfs/buffs I've seen so far seem to be marginal and don't really "make or break" the build, as far as I can see, so far at least. I understand there can be a lot of drama on the margins, and, as a software developer myself, that's absolutely valid and definitely matters, but broadly, I see nothing in here that would have me recommending people stay away from it (as I might with Claws or Super Reflexes, based on my previous experiences with those)