It was still a bit inappropriate to do that just to sell a new line of toys to kids. I think I have read somewhere that kids didn't took the death of their hero and fatherly figure lightly (I'm speaking about his first death, in the Transformers movie of '86).
Back then many kids' cartoons had "educational advisors" on their board. Even one episode of the series Dungeons and Dragons was almost shelved because the characters merely contemplated to kill Venger (their nemesis). Which is ironic considering that the tabletop game is a good part about combat rules, killing monsters and eventually defeating/killing the evil overlord.
But more on topic, apparently there will be a MLP movie next year and it was going to be like the Smurfs movie (2011) with CGI and real life actors. Fortunately someone realized that it was an horrible, terrible idea and the people responsible of this were fired and turned into
Torgo's Executive Powder. Okay that last part isn't real, but they apparently got fired before unleashing this nightmare on us. Their replacements decided to keep MLP movie as a cartoon but it will be done with Toon Boom Animation instead of Adobe Flash so, expect the quality to go up a notch.
There will also be another EQG movie and that probably means Season 7 will most likely be an half season.