So what causes this? Is it just a lack of play testing? Or is it a problem in the development process?
I really got into deciphers TCG's, specifically the lord of the rings and it was full of problem cards which was a huge turnoff and led me to just collect them and not play.
I noticed the lack of Pokemon cards in here as well lol
I playtested LoTR heavily for Decipher. In terms of problem cards, the biggest issue the game suffered from early on was choke and 'best of everything decks'. In terms of how they got made despite play testing:
I) choke, which was a huge problem in the first three sets, was the passion of one designer who was convinced it was necessery in the same way magic had counterspells. And, like counterspells decks, it was horrendously unfun to play against. Unfortunately that designer was best buddies with the high ups in the company, so it wasn't until Two Towers block that the decision was finally taken to kill choke, stop printing cards for it and print hosers for the original set cards.
Ii) 'best of everything' decks were a natural consequence of the game having a resource system that didn't care about faction or colour. Whilst the designers tried to hold them back by making you play other cards of that race to make them work, it wasn't enough and after choke was killed the best decks were just a collection of the best heroes and items in the game. That led to all the versions of Grima Wormtongue in Two Towers block, who was cripplingly powerful against a deck using tons of equipment or heores from multiple races / factions.
After the first few sets the game got a lot more balanced as the designers learnt what worked and what didn't - although you still saw some wacky cards early on in a sets testing. Ents had aversion of Merry in it that was capable of reaching a strength of over 50 in a turn (for comparison, the Balrog was the highest strength monster in the game at 16, which meant that Merry would instantly overwhelm and completely obliterate the Balrog in combat without suffering any damage).
Good times!