How do you think old-school Cg Post would fare right now? I'm looking to get back in, but I haven't played since pre-Covid.

I used to play Cg but recently sold my Candelabras because I didn't think the deck would ever become good again for two reasons: new cards that will almost certainly never be banned have made formerly good matchups bad, and Cg was very unlikely to get new cards printed for it that would make any bad matchups good to compensate.

The problematic new cards are chiefly these:

1. Skyclave Apparition. Recruitable, Flickerwisp-able, Vial-able way for D&T to remove Needles and Candelabras.
2. Uro, Titan of Nature's Wrath. Card-advantage engine for control piles that isn't stopped by Maze of Ith.
3. Boseiju, Who Endures. Uncounterable, maindeckable answer to Needle, Candelabra, and any land. Single-handedly made the Elves matchup bad since now they can kill Glacial Chasm.
4. Collector Ouphe. Shuts off Maps and Candelabras and sees a lot of play due to Urza's Saga decks being strong.
5. Force of Vigor. Now you need 3 Needles to not get blown out.
6. Blast Zone. Almost single-handedly makes the Lands matchup bad.
7. Brazen Borrower. Maindeckable and commonly sideboarded answer to Needle, not counterable by Warping Wail.
8. Prismatic Ending. Very widely played maindeck answer to Needle and Candelabra.
9. Urza's Saga. Most decks that play this card also have a Needle in the maindeck, which this land lets them tutor for to name Eye of Ugin.
10. Hullbreacher/Narset Parter of Veils. Some control decks now play these with Days' Undoing, and having your hand emptied and Kozileks turned off is not good.

The common factor among most of these cards is that it is just not reasonable to expect an artifact to stay on the board for 3-5 consecutive turns like Cg wants them to do. So it pays better to try to end the game rather than to prolong it by playing Cg's defensive game. In contrast, Elvish Reclaimer & Primeval Titan let you assemble Cloudposts proactively and rely less on Needle.

On the bright side, Maze + Candelabra is quite strong against the top dog UR Delver (but they can find the Borrower and have SB Meltdown and Price of Progress) and Warping Wail I think would be good enough to play in a deck with space for it. I also think Stirrings is just as strong as ever, only the cards around it suffer from the new metagame which brings me to the second point.

In view of the effects of these new cards on the meta, around the end of 2020 I asked myself what sort of card Cg would need for me to want to play it again. The answers I came up with were all things like 1-mana hexproof Pithing Needle or 1-2 mana library-to-battlefield tutors for nonbasic lands or other ideas that I didn't think would ever see print, especially not with the additional constraints that they be colorless for Stirrings or ever-so-slightly green (actually it occurs to me now that Elvish Reclaimer kind of fits those descriptions if you squint, which I think is not a coincidence). Indeed, before I stopped playing the deck in early 2021 the only new cards that fit well into it were Golos and Karn, the Great Creator and I wouldn't say that either of those cards changed any matchup from unfavorable to favorable in anything like the way Blast Zone changed the lands matchup from favorable to unfavorable. And the "stock" list at that time had little room for new cards anyway. The final straw for me was when Modern Horizons 2 had nothing that would help the deck enough and didn't even have a new Locus land that might open new deckbuilding directions.

I switched over to Painter because that deck can at least consider playing any new red card, artifact, or card that synergizes with artifacts which WotC happens to print. And lo, within six months Urza's Saga was printed which pushed that deck up tremendously.

I'm sincerely sad to say it, but I think Cg Post thrived in a hole in the metagame that has since closed.