Charizard/Pideot ex rely on rare candy - they mostly dont play the stage1s at all. So they open great with 2 turn rare candy double charizard/pidgeot you attache the devolution TM to whatever and use it. With 3 rare candy gone and basically no stage 1s they are DEAD.
...Not to mention, to add to the above point, the devolution TM is more dehabilitating to Evolution decks as a whole. In decks that run Kirlia for draw, a minimum of 6 counters on stage 1s everywhere, will virtually end the game by prize count unless one of those stage 1s have gone stage 2, at which point, 2 more counters are needed to put an amount into discard that will spike the need for Pokémon retrieval cards for survivability after their basics are KO'd and some prize cards drawn by opponent. Pidgot ex and charizard, prepare to fall out of meta hard post-devolution! I can imagine lost city getting banned for that reason alone come raging surf, as TM devolution could combo with it to devastate Gardy and other stage 2 decks and force decks to 4 counter-stadiums(to bump lost city) and 4 super rods or even Miriam for Pokémon retrieval from discard, or more simply, away from stage 2s altogether, all due to the devolution alone. Lost city will be an Uber strategy card that will make it too easy to win games by deck control post-devolution. Deck manipulation? Not a easy feat in the meta through this point. But I have a feeling that devolution manipulation becoming norm in the meta could be toxic for championship tcg play...
^ Hope I'm wrong, but it sounds like devolution will turn Standard almost, if not completely, into speed vs. effect prevention once more, similar to expanded. Basics that don't need to evolve to get good are the best pokemon in such speed-fests, while evolving will only serve to hurt your deck performance if not guarded by ability effects similar to toedscruel ex's. Hopefully, Devolution is not enough to turn standard into such an equivalent of Expanded in terms of game speed...
PS, Paradox basics, please save Standard from a meta where Evolution is a extreme but necessary hassle to successfully pull off without extreme cost...