Pretty much. Megas change typings, stats, abilities, and several of the designs even feel like they could've been an actual evolution for Pokemon that needed them. So while I dislike how they're temporary, I totally get why people are upset that they're gone, it really fucks up certain Pokemon.
So much amazing moments but they are gonna butcher the
To be completely fair, back when season 1 and 2 aired, from 2012 to 2014, Kingdom was not that popular, it could be compared to Golden Kamui currently. Kingdom only exploded in popularity in 2015 (and then received another boost in 2019). That doesn't excuse the fact that they cut an entire arc, but still.