To preface this, I am a spender and happily have Panther, Jackal, Falcon, Arthur, Guin, Locke, Peters, etc. That said, even as a spender it takes many pulls on the event summons to get the heroes we are looking for. I am not complaining about the number of pulls. I get that these heroes are rare, make significant impact on the power of teams, and are something I deem worth spending to get.
On the flip side of things, there are many people around E&P that are free players who still have a chance to get great heroes (epic token draws, saved gems, legendary training in camp 20). This is a huge strength for E&P to maintain an engaged player base. I want to suggest that Epic Hero Tokens be something that gives these players a chance to draw on Event Summons OR alternatively to come out with a rare Event Token type.
I know that the chances are small that you will get that Panther you are looking for with 4-6 tokens you were able to save, but that still keeps these players engaged and excited for events to come.