Marneus seems to be doing the right combination of things to be a great tokens commander for you to build around, and the perfect card to headline the Imperium deck
She was behind all four of Crown Zeniths blisteringly good gold cards, Fusion Strikes Mew VMAX alt-art, the Mewtwo V-Union four-parter, and most relevantly here, Obsidian Flames Charizard ex
For example, you could pair it with the single-prize Hydreigon from Paldea Evolved and use its ability Tri Howl to accelerate Energy cards from your deck to Hydreigon ex
You can no longer plan a simple 2-2-2 victory
While cards in the strongest competitive Pokmon TCG decks are always consistently flooding, the ability on Genesect V to refill players hands can still be useful in situations where their Fusion Strike deck is low on cards
0: Until end of turn, Gideon Jura becomes a 6/6 Human Soldier creature that's still a planeswalker