Do second charged moves make some investments less future-proof?
The Sinnoh Stone Tier List article, which was written before second charge moves were introduced, says the following about Rhyperior and its potential exclusive moves:
"Now, should it receive Earth Power, your existing Rhyperior can become Rock attackers. If it gets Rock Wrecker, TM your Rhyperior to Ground attacks. Because of its spot high on both lists, a Rhyperior you evolve now will still have some niche that you can feel safe investing in."
Assuming Rock Wrecker or Earth Power will be a charge move, a Rhyperior evolved during Community Day could learn Rock Wrecker + Earthquake or Earth Power + Stone Edge and thus completely outclass previously evolved Rhyperiors.
Is Rhyperior no longer a future-proof investment, considering the cost for a second charge move and its current usefulness with a single charge move? Similar issues apply to other species, such as Groudon (Precipice Blades + Solar Beam) or Rayquaza (Dragon Ascent + Outrage).
Answers
Rhyperior wasn't that future proof in the first place if you already had a team of SD Tyranitar, since Rhyperior is straight up worse as a rock attacker. But if you were planning to make a full team of six Rhyperior with the idea that they are half-future proof, that has indeed changed.
Groudon I don't think this is applicable to, as it's far from the best grass attacker with SoB. Any investments now are not future-proof no matter what. Rayquaza this absolutely does affect if it ever gets DA. But that could take years, and OR Rayquaza might be far less useful if you wait until after all the incoming dragon legendaries have already been released.
You always need to balance future-proofness with immediate usefulness. If you're always playing the long game, you will never use any resources and will always have weak teams as a result.
I would go further: Screw the future, play for the now. The reasoning behind this is simple: Niantic has to give new players a chance to catch up to old players. This means resources that initially were rare and hard to get eventually will become plentiful. Or they will become useless, being superseded by better options or changed requirements. One of the two will ALWAYS happen. Conversely, this means future-proofness will not happen; Niantic will actively undermine it.
Rhyperior was already 2nd string to SD Tyranitar and Groudon for rock and ground type offense respectively. I'm guilty of the following from time to time, but I think people fret about future proofing too much. Community Days show that Niantic is willing to gimp a Pokemon's usefulness in favor of a 4-hour exclusive attack. Raid days have shown that they're willing to release limited-time "upgraded" versions of Pokemon you may have already powered up - see Zapdos and Gengar as two notable examples.
You need to find a balance between future-proofing and playing in the now. I hatched a 100% Mudkip during Squirtle CD that I'm saving for the eventual Mudkip day. I caught a 98% Chimchar I'm saving for its eventual CD as well. Conversely, I've evolved two of my highest-level Rhydon to Rhyperior because I needed ground types for Heatran. I have one Groudon at level 35 and another at low 30's, a maxed Kyogre, and a maxed Rayquaza. All of them stand to be outclassed by raid day versions of themselves (maybe next summer?) but I've gotten ample use out of them that I don't regret it.
Balance is crucial. If you save *everything* for future proofing you'll likely always be behind the curve in one way or another. If you blindly evolve or power up everything that stands to be "bettered" in the future and not use it you may face buyer's remorse when that better thing comes.
