Hearthpwn

@Geoff I'm not sure why all the hostility towards your question but the coin is an imperfect answer to try and make up for a fundamental flaw in the way hearthstone is designed. The devs did the best they could and played around with many different versions of how to try to make up for how much worse it was to go second including at one point play testing giving a free 0 Mana 1/1 instead, but the winrate for going first was still way too high. Thus coin and the extra card was the best solution they could come up with that got the closest to 50/50 winrate as they could.

Even in rouge if you really look at and break down win rates, especially at higher ranks, it's still better to go first as a rogue because rogue is a tempo class and the tempo and Mana advantage of going first is still better for rogue than having access to the coin. It simply hurts less to go second as a rogue than it does with the other classes but it is always better in every class to go first. The only exception to this rule (in standard) is perhaps in druid simply because coining out overgrowth a turn earlier can make up for the Mana disadvantage of going second and the coin can be used with kel' but those interactions won't be in standard forever.

Also when to use the coin introduces a lot of skill testing plays that you would miss out on. From Mana cheating in classes that can't usually cant do that such as saving a coin the entire game for a double battle cry shutter (usually a mistake), to the simple interactions it has with triggering secrets, and everything in between are reasons I wouldn't want to lose it.