Otaku
Active Member
Problem is "playable" and "popular" usually only overlap in high-rarity cards (which they presumably do not want to make that easy to obtain, given they have only included Commons and Uncommons <and cards that would have been Common/Uncommon if they were in a regular booster> so far). Almost no commons/uncommons are both, except for occasional prevolutions of good cards. (Pignite from the last one, for example.) To be fair, a holo Dark Explorers Espeon is pretty nice. (It's actually a pretty solid support card.) They could have put a FEW more playable cards in, though, like Dragons Exalted Emolga or the Ascension (Dark Explorers) Zorua. Look on the bright side, we didn't get Bulbasaur.
Rarity should not determine "quality". Remember that TCGs are a completely artificial construct; there is no "natural law" that says "only rare cards can be good!". One of the things that has been dragging this game down in almost every set is that idea. If there needs to be something "different" for higher rarities, make it special treatments (such as holographic foil), alternate art, etc. Things that entice collectors and kids just getting the booster in place of a toy, but that don't really impact players (especially as it has oft been said we aren't the bulk of sales anyway). Did I mention nothing stops them from re-releasing a card at different rarities? They've done it before! ;-)
If the cards themselves need another difference for rarity, use it for complexity; this can make the assimilation of new cards/decks a bit more gradual and streamlined (as complex cards and combos can result in constant calls for judges). Mostly only an issue at events like Pre-Releases, but sometimes even serious tournaments can feel the pain.
Other than that... the literal job of the-powers-that-be (odds are if I try to name divisions I'll misattribute responsibility) is to provide quality cards. Have you considered how much of the Basics vs Evolutions imbalance comes because Evolving Pokémon are "filler" and rarely contribute?
TL;DR: Rarity (as in what the symbol indicates) of previously printed cards should not prevent them from showing up as promotional cards.