With call energy and an extra Bebe's, you can get DGX out on t1-t2 pretty easily. Unless you can drop a Mesprit on your bench, bright look helps too. The goal would be to start deafening on t1 or t2... And dragon rush won't be hard at all t2 with DCE. But I agree with your assertation - it's not foolproof, but it can cause problems for SP.
You seem to be talking about Dialga/Garchomp here, and that is an exception since it is focused on Dialga G, wants to start with it, has the energy for it, etc.. Something like Luxray/Garchomp will only be running Dialga G as a tech, if at all. Yes, they can Call for Dialga G and then Bebe's, but they also need to get the energy, and Deafen isn't much of an issue with Spirtomb evolving for you. Dialga G can't stay active if the Body is supposed to last through the game (it's useful to stop Maternal Comfort as well, which SP also sometimes has a problem with) because it'll get KOed by Gallade, so it will have to get to the bench somehow, wasting energy in the process. The very act of getting it out is proof enough that Spiritomb did its job-- it forces the SP player to play around it. Gardevoir only needs a few turns of that and it is ready to go.
You're right that Bright Look is usually devastating if it goes off, and I know it definitely can under Spiritomb (just not with as much ease). I play both decks regularly. That and Dragon Rush (with DCE) remain the two biggest enemies to GG or most decks. Without Spiritomb though, Luxray/Garchomp will consistently be able to disrupt GG's set up; with Spiritomb, you throw an obstacle in their way and force them to get around it, which they may or may not have the resources to effectively do. That's my main point-- it complicates things for them. It is also amazing for Darkness Grace.
This is probably your best point. Personally, I don't like the toxitank combo as a tech. It's way too clunky and as you said, it fails to a power lock. Uxie is a much better option, but it will get revenge k'od. That's the hardest thing about countering poison types, because they can just hit you back (it's like the flygon / garchomp thing). This is the biggest problem and I'm trying to find a way to counter w/o getting revenge KO'd... Or at least counter and force Gallade to flip a bunch of prizes to OHKO. I disagree though with the uxie lvl. x thing... A good SP deck has no reason NOT to run a 2-1 uxie line. That said though it's REALLY easy to get Lucario GL on the bench... SP has call energy and roseanne's....
SP lists are very tight. The only deck I can think of that frequently runs more than 1 Uxie is Palkia G, and although the lv. X is an all-around good card, it isn't a priority inclusion, which means it won't be showing up in a huge majority of lists like, say, Toxicroak G promo. It's also not easily searchable, especially if you used up a Bebe's already on Dialga G lv. X. If it does come out though, I agree it is a good counter to Gallade, especially if Garchomp C is primed to use Dragon Rush on it if you miss the OHKO due to Expert Belt and it runs to the bench. Its immediate death to Gardevoir is a significant drawback though, and because of that and the resources needed to get it out to begin with, it isn't that devastating to the deck in my opinion.
Agreed - the Gallade to Dialga matchup is bad. Dialga to gardevoir isn't though. Dialga doesn't rely on powers, it shuts down all bodies like Nidoqueen, and it resists Gardevoir. If you can slap 3 special metals on Dialga, the psychic lock will only do 10-30... You'd have to bench Dialga until Gallade was dead and pray the plox player has no poke blower+. Gallade's also good against Luxray, unless the luxray player can get a sunyshore out, the gallade player won't have to even flip prizes. True, you can't use expert belt, but you can just save it for later. Gallade can really only do his thing flipping prizes about twice if you KO the dialga anyway. A dialga chomp player can always switch garchomps if they run a 2-2 line and keep sniping your support off the bench.
Gardevoir against Dialga G is rough, but the deck does rely on Powers-- Claydol is essential to get the Special Metals, Garchomp C lv. X is essential as a healer, and Galactic Switch is important too, to a lesser extent, to recycle energies, including Warp. The presence of Gallade on the bench should make the Dialga G player wary of putting Special Metals or Expert Belt on Dialga G, allowing Gardevoir to hopefully only have to deal with resistance. Wager can take away the ability to constantly Poketurn by chaining Cyrus', and no Galactic Switch also hurts that strategy. The whole game would be like chess, and it would come down to a lot of factors such as how Wagers went down, how Gallade was used and handled, how quickly both decks set up, and so forth.
It's a pretty fair matchup, it's just not that plox will totally pwn SP tho...
I agree. I was just pointing out that GG does have tools at its disposal to help in its SP match-ups, which of course include other decks beside Dialga/Garchomp.