That sounds... unpleasant to play. Turn 12 of a Commander game. Most people have about 3 creatures out, the green ramp guy has 8. Cast this! Woo! Everyone grumbles, gets out a pen and notepad and starts scribbling "6/6 trample", "4/4 flying artifacts-have-shroud", "5/5 1U:blink me or my pair", "6/6 on attack burn for 3 divided"... 5 minutes later the game resumes with the battlefield now covered in scraps of paper...

It's not even like you can use the original cards to represent the tokens, because they're sacrificed, which means they're sitting the graveyard ripe for all the black and/or green and/or white decks to reuse.

Maybe it'd be better if it exiled then? It doesn't solve all of the problems, but it won't be that much more problematic than, say, Clone Legion...

Exile would definitely be better. But fundamentally, Clone Legion is a 9-mana sorcery and will often end the game unless it's immediately followed by a boardwipe. This doesn't actually really directly affect the board - it still leaves the board with all the stalls and complexity it had before - and it's a tricolour legend, making it perfect for a commander and thus setting up the expectation that it'll get cast several times each game.

Much better! Cool, in fact. Like a more interesting take on Triad of Fates.