You guys seriously need to stop bashing Tsareena, especially when you're refusing to acknowledge any of its merits over other spinners, which are plentiful. Comparing it to a Pokemon as shitty as Lurantis is also absolutely asinine and doesn't even contribute to discussion. The same can be said with saying it should drop from UU when we have crap like Sylveon and Darmantian still hanging around lmao. I don't think it should drop to B-, much less C+, though definitely see some of the reasoning behind a potential drop. Regardless, I'd like to go through everything that Tsareena has that is more useful than the likes of other defensive spinners, so you people that don't even seem to have used it can understand why it actually deserves its current rank:
With its typing and Trop Kick, it actually can hold its own against some of the tier's most common hazard setters - By virtue of Tsareena's Grass-typing and Trop Kick, which is actually an extremely useful utility move, it can more reliably deal with the likes of Swampert, Hippowdon, and Gliscor in comparison to Tentacruel and Forretress. Tentacruel can potentially burn these Pokemon with Scald, but isn't as reliable since its weak to Earthquake, which all will always run (Gliscor can also avoid burns with Poison Heal). Forretress can tank their hits, but doesn't have any recovery and is just worn down and saps momentum as a result. Tsareena, on the other hand, can use Trop Kick to super effectively damage Swampert and Hippowdon and lower their attack more reliably than Scald and actually resist Earthquake. Gliscor also doesn't appreciate the attack drops, as after being hit with just one Trop Kick defensive Gliscor sets become really passive, with only Toxic to sufficiently damage what tries setting up on it.
Edit: There's also Krookodile if we're talking about Pokemon that commonly set rocks, and Tsareena's also a lot more reliable against that as well, since Krookodile especially hates the lowered attack and threatens Tenta and Forretress with powerful EQ and Knock Off attacks.
It has recovery - Tentacruel and Forretress are really hurt by their lack of recovery, since they're prone to being worn down and thus, can struggle to consistently use Rapid Spin throughout long matches, unless of course preserved. Tsareena, however, is able to consistently spin without worry at all, as it can recover any health lost in the process of spinning with Synthesis. This is particularly useful in, as stated before, especially long battles, where in time, Tentacruel and Forretress will just be worn down and faint. You could argue that Tentacruel and Forretress can just receive Wish support from another Pokemon on your team, but Tsareena won't need that and as a result, won't take up a teamslot for its own support, which is honestly such a nice perk over its competition.
It has unique tools that allow it to support its team - People here are arguing that Tsareena is outclassed by Tentacruel due to its lack of utility. This is honestly such an inaccurate claim, as there are plenty of tricks that Tsareena has up its sleeve that allow it to adequately support its teammates and in ways that Tentacruel can't or at least not as reliably. Trop Kick is easily one of the best things about Tsareena. You guys are arguing that it's piss weak, but it doesn't need to be powerful. The move provides Tsareena with good utility in that it guarantees the lowering of attack of foes, which is quite useful compared to the 30% chance of Tenta's Scald. This discourages switching in from foes that you'd think could actually switch in, such as Infernape, Doublade, Entei, Cobalion, and Scizor. This also allows Tsareena to easily support its sweeper teammates in that foes with attack that's lowered enough in time become quite passive. Tsareena also has Aromatherapy, which is a move entirely unique from anything any spinner in the tier brings to the table. It allows Tsareena to win 1v1s against bulky waters by healing Scald burns, and also takes the weight off of a team's shoulders if they're worried about both status and hazards but don't want to take up two moveslots. There's also U-turn, which is a great source of momentum and allows Tsareena to reliably support its frailer teammates as a slow pivot. Between Trop Kick, Aromatherapy, and U-turn, Tsareena is more than capable of providing for its team, and in plenty of ways that are different from Tentacruel.
Lastly, Tsareena isn't as passive as other defensive spinners - I've already told you why this is the case for Tsareena. Unless your opponent is Bisharp, which threatens every spinner, Tsareena can discourage setup by using Trop Kick to lower the attack of foes that may try accumulating stat boosts against it, like Conkeldurr, Doublade, and Decidueye (which are all some mons that as you guys said, Tsareena seemingly can't do anything against). Tentacruel has Scald and Acid Spray to try making up for its passiveness, but we reside in a Steel-heavy meta, so Acid Spray will at times be a waste of a slot, where as mentioned before, Scald is much less reliable if one would hope to lower a foe's attack stat.
I think that while a drop to B- isn't too unreasonable, that Tsareena's current placement in B is justified at the moment, and that you guys seriously need to at least shed some light on these mentioned perks before immediately saying that because of its worse defensive stats Tsareena is automatically outclassed as a spinner.
Although this post is already quite long, before leaving I'd like to shed some light on Bruxish. Bruxish isn't a great Pokemon, but honestly is much better than what currently resides in C-. It a gigantic threat to offensive and defensive teams alike with its Swords Dance set, and overall has a niche that compared to even C-'s best Pokemon in Venomoth, Minior, and Rotom-Cut, is more appreciated in the current and more consistently can be put to use. Thanks for reading!
TLDR: Tsareena has plenty of merits over Tentacruel and Forretress in that it has recovery, isn't as passive, has better matchups against the tier's best hazard setters, and also has plenty of unique utility options that allow it to support its team in ways that the other spinners mentioned can't. Bruxish should move to C since it's good af compared to everything else in C-