The ability to sacrifice a creature to create a Clue pairs extremely well with cards that produce disposable bodies
You're probably going to want at least three to five colorless mana sources to help cast any cards in your deck that require colorless mana to cast (provided you're only playing a few of them)
Both Qumulox and Broodstar being double blue are just far too onerous on the deck and building aroudn them properly would lead to a very different (and much weaker) sort of deck
One final note: its easy to hand out terrible gifts that completely lock out players from the game, whether it kills one player immediately, like Leveler, or just prevents them from playing much Magic , like Sire of Insanity
With the rise of grading in Japan, and in general how things have been going the past few years, shops look to align their prices with what they could sell for online
The Pokemon TCG serves as a fun mirror to the mainline Pokemon games insofar as they recreate the mechanics present in the games in card format