Even if this card was added to todays meta, I still don't think it would see play.
The PokePower Garchomp has is an important reason for the success of Garchomp, and the only reason decks such as DialgaChomp work. There are no SP's left, so the PokePower would be completely useless.
The attack is ok, but though it can ko a assortment of basics and a few Stage 1s (Gloom, Duosion, etc), it cannot knockout an Eeletrik, and because of Pokémon Catcher sniping isn't the same anymore. The only matchup in my opinion where Garchomp C Lv. X could be useful is against The Truth. I makes it so The Truth player can have no damage on Reuniclus, and a lower amount of damage on all of there Pokémon. If any Pokémon have the classic 10 HP from ko, Garchomp can just knock out that Pokémon. There are also no more pixies in format which means no more easy prizes for Garchomp.
110 HP is not the usual perfect amount or normal amount of HP anymore. By using Garchomp, you have basically guaranteed Garchomp be knocked out by a Zekrom, Reshiram, Magnezone, or Tornadus the following turn.
Its typing is much better though. In MD-on, there were cards such as Ambipom that could knock out Garchomp C Lv. X the after Garchomp did something. Now, the only card that hits Garchomp C Lv. X for weakness is Tornadus. Though that still isn't a great card to be weak too, its a better weakness than some Pokémon have. At least it doesn't have a weakness to lightning, because it would make a difference against Zekrom. However, in a way it's typing is also worse. There are just about no cards that it hits for weakness.
Garchomp actually got better though. There are more Pokémon that can be donked by Garchomp. I remember at States I was surprised I was donked out of cut by a Garchomp C. Now there are more Pokémon that Garchomp can donk - Solosis, Cleffa, and all the other babies such as Pichu.
The free retreat is a nice luxury - most cards in format do not have a free retreat cost now.
The stats of Garchomp are basically the same. Same typing, same ability to be knocked out. 50 for {C}{C}{C} is now bad. Tornadus out classes it, along with the dragons who also have energy acceleration and a higher HP.
Its single retreat cost is okay, but much better than a lot of the basics in format. It is above average.
In conclusion, despite a good matchup, Garchomp C Lv. X does not have what it takes to be a force in our meta today. If the Power was changed it would be a bit better, but this is a ohko format, so even healing won't have the same effect it has on a game that it used to. The donk factor is nice, but you still need a Double Colorless Energy to donk.
