As for the best of the new creatures, O'aka, Traveling Merchant turns your excess counters into carddraw, and Maester Seymour grows creatures of your choice as you grow him
There are a lot of Espers in the series, after all, so to make them all white/blue/black would be hugely restrictive
In comparison to modern eras like Sun & Moon, Diamond & Pearl's top cards (with available prices) can't compete with these modern marvels
Magikarp is the most obvious example, since that was created as a very weak Pokemon that evolves into the much more powerful Gyarados
Seismitoad's Pokemon TCG Black Bolt Art Rare Is Worryingly Expensive Seismitoad is not a particularly popular Pokemon
The drawback of losing 1.5 life per turn is not a significant deterrent in a game which ends within 5-6 turns and starts with 40 life