Thats the reason, a single deck of these cards contains around 78 cards with highly visible imagery
In theory, with a Naban, Dean of Iteration on the battlefield, you only need half the number of blue mana symbols on the battlefield to make Master of Waves good (for example, in the worst-case scenario where you have just a Naban, Dean of Iteration and a Master of Waves, you'll still end up with 10 power across five bodies, which is a pretty reasonable deal for four mana, and if you throw just one other Wizard into the mix, things cat get out of hand really quickly when Master of Waves' enters-the-battlefield trigger is doubled)
Muse Seeker is worse due being much more fragile, however looting is more powerful than rummaging, which somewhat compensates
You can't cast Victimize targeting only one creature card
How many creatures should be in a Magic: The Gathering deck