Magnetic Pull will be as reliable as Cramorant V's Beak Catch. It's not terrible, but that's just how it is. It's not like N or Judge didn't exist before (granted those cards shuffles your deck instead of putting your hand to the bottom).
For G-Max Rush, while Boss is also an inveitablity much like Marnie, I haven't seen too much Escape Rope around, at least on the big meta decks. Probably they play a copy in lieu of a Switch but that's about it.
I've mentioned this before but Metagross VMax has the option to run a Zeraora V as a follow-up attacker. Since you're likely to team Metagross with both Bronzong and Octillery (Rapid Strike card, might as well!) the LCC cost of Zeraora doesn't seem to expensive - fetch either Spiral Energy or the Zeraora with Octillery, set it up, then Saucer/Metal Transfer to Zeraora, bam 100 + 160.
Of course on paper sounds great but it'll need some playtesting to figure out and I'm pretty excited with what I could do with it. Then even if it's bad I'd still play it just because it's Metagross.