If you aggressively Power lock your opponent from the outset of a game, regardless of what deck they're playing, you should elevate yourself to a position above them, with back-up ready so that even a "heavy blow" such as a Take Out or an Extreme Attack on something crucial (ie. Palkia G lv. X) doesn't derail you. The primary reason Palkia G wins is because it denies set ups, and if you fail to deny the set up of a deck with hard counters to you, it is likely that you will lose or face an uphill struggle.
For example, straight Machamp is undeniably an unpleasant match-up because you're forced to play Unown G over Energy Gain, just to prevent Take Out from running right through your whole field, and you're still vulnerable to losing prizes on Warp Point/Pokeblower/other switching cards, as well as Relincanth sniping. However, if you Power lock them before they get a Machamp out, and Hydro Shot/Bright Look their Claydol to clear it from the game, you'll likely just be dealing with Machops/Machokes/Uxies etc., and you can build responses to any Machamps that do materialize. Gengar is another deck that can pose trouble, with all of its own disruptive tools (from Pitch Dark all the way to Level Down) combined with Nidoqueen, which, if you let them get it out, will make it nearly impossible to avoid Feinting Spell or abuse Pearl Breath. If you prevent a Gengar swarm backed by constant Maternal Comfort healing, you won't have trouble. KOing Gastly and Haunter is easy.
Just watch out for Luxray GL/Garchomp C, which will often run Sunyshore and negate your Toxicroak G promo response to any Palkia G KOs from Luxray GL.