So I've been using this class as part of a pile of mods that me and some friends have been toying with. I think, conceptually, what Florist presents is fun-- I like thinking about the vanilla classes in terms of what synergies they operate best with because of their base kits, and having a class that leans into the specific idea of 'I Am The Biggest Debuff Liker In The West' is a fun idea. The core conceit of your special deciding the functionality of your secondary is cute. The art is lovely, Florist really has her own aesthetic vibe and I appreciate it. I wanna lead with the positive stuff to establish that I think this class has been fun to play with and I like it overall, but I do think there are some parts of the package here that could use tweaking.

First of all, I think the upgrades really err on the side of too weak or not impactful enough. The vast majority of the Secondary upgrades just... aren't ever worth taking? None of them are game-changingly, build-definingly strong; they're basically all just small changes to the functionality... and none of them are stronger than just having it as a GCD with a 4 second cooldown. Why would I ever take Opal Secondary, for example? It's an upgrade that basically accomplishes nothing but make the GCD of a button I hit once every ~5 seconds slightly faster, and remove the cooldown, despite the fact that I would only ever hit Secondary to reapply my debuff associated with my special? Garnet Secondary makes its damage go from 'abysmal' to 'bad' while extending the cooldown to significantly longer than the average debuff it inflicts, cutting into your debuff uptime, a crucial aspect of the class' rotation. Ruby Secondary is a fun idea that I like a lot conceptually, but it's so deeply ingrained in the idea of working with Ruby Special that getting one without the other renders them mostly worthless.
And this is all just me talking about a couple of the upgrades for Secondary-- me and my friends have done multiple runs with this class and frequently we wind up only purchasing two upgrades before Pale Keep because nothing else is especially worth adjusting your rotation to take. For reference, a thing I appreciate about the vanilla classes, as someone with too much autism for this game, is that basically any upgrade you can take is, at worst, a DPS gain. The least impactful thing you could take on Defender will still buff your special's damage by between 20-40% or something. Meanwhile that same class also has Ruby Primary, which completely reroutes your rotation due to its sheer power and can make me entirely reevaluate my build if I see it mid-run. The most I get for that on this class is... I guess Ruby Secondary. Maybe Opal Special, but that's mainly in terms of 'how badly does it grief my party if I took this and cancelled everyone's poisons and curses'.

Also, and this one's not your fault as the mod maker but I do think it's something to consider-- Because this is a modded class, it's something you'd only play in modded runs. If your run is modded at all, you're probably also using modded items. If you have modded items in the pool, proportionally that pushes debuffs out as something you'll be seeing every run. I appreciate how generally the debuff synergies with this class care about debuff count and not what the specific debuff is, I think that's smart future-proofed design, and I appreciate how that means you still benefit from your allies taking debuffs as well, but for things like your Special caring about specifically Sparks and Poisons and Ghostflames and Burns, it gets to be a little bit stifling-- There are only four shops and six chests in a run, that's only so much opportunity to run into synergies. It's very feast-or-famine in that sense. There's just not much room for you to get a run that is incidentally powerful, if that makes sense-- 'I stumbled into a combination of upgrades and loot that I managed to make work'.

All that said, I think my number one priority suggestion would be to reevaluate the upgrades. Using the shop as a means to really hedge against low-rolling runs where you just don't get offered Spark or Bleed or Poisons would be the safest and most sensible thing to do design-wise, I think. If i'm playing Florist, I personally am not keen on Vanish or Haste on my defensive for basically any reason, because my primary gameplay doesn't benefit from those things-- but for example, did you know Bleed and Sap actually apply their bonus damage to DoT effects? A Bleed will make a Poison hit for 20 additional damage. I think I would absolutely take a Defensive that replaces Sweet Scent as a raid buff with a Bleed-- that's a universal damage buff instead of a specific DoT damage buff while also itself being a debuff. Or, what if a Primary upgrade was made to also inherit the debuff your Special applies to your Secondary? Getting a second poison in a different color to spin two DoTs at once before loot would be huge. It might cut into the ability damage you're doing but lean into the synergies more, and that's a decision I would be interested in making.

And while I think it's less mission critical than all that, I would also personally really like to see more impactful functionality changes across the remaining upgrades. Again, those secondary upgrades are generally the worst part of this class if I'm being brutally honest, my ass is never taking Sapphire Vine Shot are you crazy. Maybe one could be like Spellblade's Emerald Secondary, becoming an automatic oGCD and firing 'approximately' as often as necessary to maintain debuff uptime. In my experience, any upgrade that takes an ability off the GCD is, frankly, probably the best upgrade you can get in that slot in a vacuum. I think it could be fun to have an automated secondary that maybe leaves a small window where it wouldn't have uptime on the debuff-- like a 6 or 7 second cooldown but the debuff is 5 seconds, meaning it might be slightly worse for you than if you were manually applying 100% uptime, but also, it's still free damage and you never have to spin your GCD to press the button. That's much more interesting math to need to do, imo. And while we're at it, it might be fun if there were a Secondary upgrade where the idea is it suddenly becomes the focal point of my rotation-- again, thinking Defender Ruby Primary, or maybe Bruiser Emerald Secondary.
I think the inkling of intent for that seems to be there in a couple of cases...? Considering the current effect of the Opal and Sapphire Primary upgrades...? But consider that if I took those at the first shop, my rotation would be 'press X every 4 seconds'. That sort of thing is funny when I'm lategame as Defender and my GCD and my cooldowns are so prohibitively long that I spend most of the fight doing nothing, but also when I act it is so earth-shatteringly powerful that the fight is over in 11 seconds. On Florist, though, getting into that situation in just one upgrade... isn't very appealing, especially when the payoff isn't even very high. Maybe the default Secondary doesn't need a cooldown because the idea of only pressing it every so often is already enforced by 'I only want to press this to reapply my debuff' anyway, and then we can save the cooldowns for upgrades that are on some ♥♥♥♥ where 'okay, this has an 8 or 12 second cooldown, so you lose some debuff uptime, but it deals like 500 damage now', which would singlehandedly make secondary-scaling loot more potentially appealing. Things like that are what i'm talking about.

To spitball a completely random number off the top of my head with no real statistics applied to it whatsoever, I think somewhere between 3 and 5 upgrades total, spread across Primary/Secondary/Special/Defensive being retooled to somehow inflict additional debuffs would make for a good safety net against runs where you just don't get offered good debuff loot. Consider at least one Secondary upgrade convincing enough that I would maybe try Secondary Florist as a build, where it's either spammable enough or strong enough to be worth building into. Gimme the sort of upgrades that I would be thinking about in the potential future tense when looking at my Outskirts loot. That's a big part of what makes class design in this game so fun, personally.

Anyway, overall, I really like what you're putting down here; the class as it exists is fun enough that I'm keeping it in my friend group's modlist, at least until someone really craves playing Wizard again. I'll be really looking forward to seeing whether this mod gets updated and if my bugbears with it get fixed, I want to see this go from Good to Great, I'm totally rooting for you here.