Alright, looks like there's a bit of controversy in the thread about how people view Shadow Tag as itself - I personally think the main problem is that Gothitelle's usage (the main abuser) is just way too low to form an educated opinion on Shadow Tag unless you have seen it in tournaments, which is where the main idea comes from. I personally think, as FardinAG mentioned, this suspect may have started too early due to the lacking usage and unreliability of the ladder to determine actual effectiveness, and as such people have not been able to form an opinion of Shadow Tag's rather brutal effectiveness. Here are what I think are problems within Shadow Tag that might warrant an unban:
1) Difficulty to fit trappers on a team
The main problem I see with Shadow Tag is the fact that it is often just better to add another offensive Pokemon to the team rather than use a slot for something that can be unreliable in how much work it will put in each game due to the diversity of team playstyles. The thing that makes Gothitelle so potent is the fact that, with Shadow Tag, it is able to remove the most common defoggers in the metagame in Arceus-Ground and Fairy, making most bulky offense and balance teams vulnerable to the gap that it has opened. Some playstyles however, may need to target offensive teams with their remaining slots, making Gothitelle either a last thought or something a team
has to be built around. It is this problem in usage that makes Gothitelle/Gothorita rather unreliable in an average matchup, which can seriously ruin a team if it has to operate on 5 Pokemon. As much as Gengar-Mega might warrant a mention here, it basically has to exchange a moveslot to trap Blissey, and it is completely unable to deal with Arceus-Fairy and Blissey if they have coverage (which Arceus-Fairy often does).
2) The exclusivity of Shadow Tag on their respective members is the broken part, therefore making the trappers broken as they utilize the ability to an extreme.
Now, you might think this is turning into a similar post to Highlord's. However, I have a few qualms about the claim made:
Section 1: The Nature of Shadow Tag
Shadow Tag is only powerful in conjunction with a Pokemon's other capabilities; therefore, Shadow Tag is not inherently broken.
Example: Shadow Tag + sleep-inducing moves/Encore/Taunt
Shadow Tag alone does not facilitate a ban; combinations of abilities, moves, typing and stats are what determines the effectiveness of a Pokemon
Whilst I get the point that you try to address, take a look at the two components. I definitely agree that the combination is what makes a Shadow Tag trapper
effective, but it is not what makes it broken. Take a look at SleepTrap Gengar-Mega - despite Hypnosis' 60% accuracy, the combination of Shadow Tag and its ability to hax through walls with Hex + Hypnosis, obviously called for a complex ban that just had to be made because it was so ludicrously uncompetitive. The fact is, taking a look the moves alone, they wouldn't be too effective other than to create setup
opportunities for teammates. However, Shadow Tag, even on any offensive or defensive mon, has such incredible augmentation that it can be used to incredible efficiency, dismantling cores without any competitive input from the opponent at all. All they can really do is just hope the trapper gets unlucky about it.
I also heard you talk about Pursuit as a trapping move, and compared the two - whilst a rather ridiculous comparison for the ranges of things that both can trap, you bring up a relevant point about how trapping can improve a Pokemon's viability, even if it targets a small range of the metagame. The fact is, Shadow Tag is ridiculous at doing this, making a Pokemon as bad as Gothitelle so potent in Mix and Mega because of it. This still goes on to the nature of Shadow Tag, however, the points being mentioned point strongly towards Shadow Tag being the broken aspect of a Pokemon, not its movepool, or its stats. These do contribute, as core stats do, but Shadow Tag amplifies this so greatly that it is obviously a problem.
3) It is too early to form an opinion on Shadow Tag due to the extremely low usage of such Pokemon.
This is more of a problem I have - whilst I am practically stuck believing that Shadow Tag, in almost all cases is broken, it is often never an impact on a team. In the cases which I do consider it, often times a good team will have fallback points without relying on a single Pokemon to do a job unless it is absolutely necessary to do so. Take a Groudon-Primal counter for example - most teams will have ways of damaging it or pressuring it heavily with offensive momentum rather than with their dedicated counter, such as Arceus-Ground. There are also alternatives to this Pokemon that don't lose to Gothitelle such as Hippowdon, however they do not have the movepool that Arceus-Ground can utilize to help support the team - neither does it have the Speed to deal with such a threat consistently, having Swords Dance variants break through. Other alternatives may have an even bigger problem, such as lack of recovery, loss to a coverage move, et cetera. This unfortunately pressures teambuilding into utilizing support Arceus to deal with threats that Gothitelle can remove consistently, making it considerably harder to build with it in mind. However, the incredibly low usage of Gothitelle almost means nothing against this - often times I build without it in mind at all, because most players in Mix and Mega do not know of or understand how Shadow Tag can be used so effectively.
This is mainly relating to Fardin's first post - however, I also have some of my own opinions for the post:
What goth has done to ubers had a great influence on starting up this suspect, since the 2 metas are quite similar.
if goth wasnt relevant in ubers or even ag, im 100% sure this suspect wouldnt be happening
I'm adamant the main reasoning for this isn't based on Ubers or AG. In the OP, the main reasoning is expressed through Quantum Tesseract's post - the very fact that Gothitelle can so efficiently trap common Pokemon in Ubers that just so happen to mainly relate to Mix and Mega is what I feel the reasoning relates to, and is why discussion has sparked up in both areas. However, I do agree that its usage in Ubers is what has caused this knock-on effect to occur in MnM - which has caused realization of this Pokemon.
As a conclusion, I personally do believe that Shadow Tag is broken. Whilst opinions may be different, and whilst other people may attack them and try to change them too actively, I think that both banning and not banning have their reasons laid out, and serious discussion has finally started on an issue which - to be honest - should have been sparked before this suspect test ever happened. Whilst I agree that a suspect test is the best way to go about this, the fact that not a single relevant MnM tour has come out before this Pokemon was even mentioned in Ubers to now where Gothitelle has been used may have made it too early to tell how broken something truly is.
and before I ask - please try to keep civilized discussion in a suspect thread. Even if it is controversial, even if it's trying to fix stupid arguments (which I personally do not think there is, just misunderstandings), being calm about it would do much better to make people potentially understand their arguments and reconsider rather than just attacking them because they might not have the views that you would have for an argument.