Umm.... what level are you? And what rank are you?
For some reason I am assuming fairly new otherwise you would know that Klepto is only used on about 4 champions.... Ezreal being one of them yes. However with him he actually has to hit his skill shots or go into auto range to do something with it. If you can not stay behind minions, do not know how to dodge, or if they are really good at predicting your movements..... of course the Ezreal will make better use of it. Also it does not always give the gold bag.... meaning it is random how much he actually earns, and the bag itself has random amounts in it.
Next thing you know, you are going to be complaining about supports that have SpellThiefs Edge just using an ability and getting gold.
It is not "busted" or "broken" however if used effectively it can feel like it to the uneducated in the realm of League.
Also, Glacial is used by various mid laners like Veigar, and Ahri.... supports like Morgana and Sona.... various ability power champions who do not mind using Twin Shadows or that ice shard firing hextech thing (usually both). It gives champions who do not have a slow... an extremely hard slow that can be utilized very well vs semi immobile champions (those who do not have a dash in their basic abilities) but still useable for most any situation including vs mobile champions.
Unsealed Spellbook is used by various people to varying degrees of effectiveness..... I use it on Blitzcrank or Syndra from time to time to troll the enemy jungler by starting smite and then taking the enemy junglers red/blue buff and then smiting it from them... then still have the ability to use Ignite or cleanse or barrier etc. Others like Top laners can use it to get teleport and tele into lane with a shorter cd on it. Ive seen Mid laners using unsealed as well..... it is just dependant on what the player wants to do.