One comparison I think needs to stop being used is the comparison of Giratina-O to a Mega. The use of its item slot is the only particular resemblance I see.
- The item itself boosts the power of Giratina's STAB moves, compared to the Mega Stone inducing the form change and nothing else.
- Giratina is Giratina-O at the outset of the battle. Megas still need a turn to change, which in some cases can be very limiting to them (see Altaria or Zard's SR weakness and Base Diancie's awful speed)
- Giratina-O does not occupy your Mega Slot. One thing that is limiting about Megas is that because of the one-per-team limit, you can't use them alongside each other (imagine the kind of defensive cores you could make otherwise with Zard-X and Venusaur, for example). Giratina-O is able to support and be supported by other Megas because it lacks that stipulation.
The net result is that Giratina-O is significantly more splashable than any Mega Pokemon, since it can fulfill its row without limiting tem-building beyond typing overlap or such like any other regular Pokemon. That said, Giratina-O brings a LOT in that one slot, arguably more versatile than some Megas, between playing a bulky wall, a Mixed Attacker, an offensive utility mon, among others people will no doubt manage to find through experimentation.
Despite my dismissal of such comparisons, I think what makes Giratina-O so effective in the current Meta is similar to why everyone was hyped about Mega Sableye: Role compression. Sableye was a big deal to Stall teams in early ORAS because he provided hazard control, excellent defensive synergy, pseudo-status immunity, was able to spread status himself, and could serve as a win-condition or utility mon with CM or Knock Off.
Giratina-O, similarly, can be a wallbreaker itself, a bulky attacker/tank, an outright wall, a blanket check to some of the hardest hitting wallbreakers in the tier, and provide either Hazard Removal or Status depending on if you run Defog or WoW, all on more or less one set with some EV tweaking. Its massive bulk (uninvested I believe it still outstrips Heatran, for example) and pretty good typing (The weaknesses suck, but most Dark moves are KO, Ghost is mostly on Gengar, which leaves Ice, Dragon, and Fairy, easily covered by a teammate, not to mention Levitate giving it Spikes immunity) make it incredibly difficult to crack while it lays into the opponent with high BP moves such as Outrage or Draco Meteor, not to mention phenomenal coverage while it's absorbing blows.
The reasoning to suspect Giratina-O was:
"the abundance of defensively oriented teams led us to believe that a mixed attacker with great defensive and offensive typing will probably give back some vivacity to the tier."
However, the thing many of us have noted, and the opening did as well, Giratina-O's arguably greater contribution to a team is how many potent threats it can check in one slot. I don't play as much on high ladder, but 23 of the Pokemon in S-A ranks are primarily found on offensive playstyles or play offensive roles, compared to 7 that primarily play support or defensive (not counting Mons that could do either such as Mega Altaria or Mega Scizor). That just makes me surprised to find that the metagame is evidently more defensive than offensive apparently. I just fail to see then how introducing Giratina-O will move the metagame away from defense rather than towards it.
Last time I saw the viability thread, many people were noting how hard pressed defensive teams were to deal with things like Mega Metagross and Landorus-I (I think M-Latias moved from A- to A just for being a consistent answer to the latter). If, despite that sentiment, Defensive teams are indeed dominating, I feel like Giratina-O would only make them moreso, since it brings so much utility as well as stopping so many of these otherwise problematic attackers. Giratina-O's offenses and coverage aren't anything defensive teams probably aren't ready to deal with (Kyurem-B presenting at least as much trouble from a raw power perspective), but offense is going to need to put a lot of work into breaking the demon dragon. Defense doesn't have any one mon that can be pointed to as hugely responsible for its success, but offense has monsters on its side like Keldeo, the Genies, and Mega Metagross: 2 of which were banned last gen and are or have been S-Ranked this one, another S-Ranked since its inception (discounting the Salamence month), and another that dominated last Gen and continues to be a top threat despite losing something in almost every transition (XY cost it rain, ORAS hurt its speed tier). Offense has more mons that either have been or that could warrant suspect testing (I have no opinion on whether they should or not), yet defense is the dominant playstyle, which I just find very odd to comprehend.
With all that said, I'm not sure how big of a fan I am of the idea of suspecting a Pokemon just for the sake of shaking up the tier rather than them being outright unhealthy for the metagame. If defensive teams are becoming more abundant, is that a sign of the tier being stale? Perhaps, but in my experience, Defensive playstyles are more consistent to play with and win with for a skilled player, since the playstyle is meant to last and thus is more prepared to recover from mispredictions. Despite this, I'm seeing a lot of experimentation, tons of posts in the "Good Cores" thread and team ideas that convince me plenty of people are experimenting and interested to see what they can try. Maybe the overall playstyle of the metagame is sitting securely, but I don't feel like the tier is significantly centralized, as it was with the presence of other suspects like Deoxys (HO), Mawile, or Aegislash (just around him in every playstyle). Giratina-O, if it does enter OU, has clear potential, whether or not it breaks the Metagame as things like Salamence or Kangaskhan did, very much centralize the tier around having to play with and against him in virtually every match. Maybe it'd be less match-up reliant, but if every match up is basically "Giratina vs Anti-Giratina", "Giratina v Giratina", or "Anti-Gira v Anti-Gira", that sounds like an even more potentially stale metagame.
I'm not sure I'll have time to ladder, nor do I think I'd make Reqs if I did, but I thought as a lurker of many years I should share my thoughts on this suspect. If Giratina-O proves to indeed help the metagame's health and diversity, I'll welcome and use it with open arms, but this is something very experimental and seldom tested we're toying with.
