The most entertaining run I've done in a long time (and I've done many runs) was a LFT playthrough with a Mime in the party. Ended up being enjoyable enough where by the end I was wishing I had done two Mimes. Really fun class to mess around with.
SCCs always seemed a bit boring to me since my favorite part of FFT is customization. Forfeiting that and constraining your entire party to be duplicates of each other just isn't for me. I did enjoy the Random SCC though, where before each story fight you randomly select a class and you play the next story fight (and all fights after that up until the next story fight) under SCC rules for the selected class. To avoid grinding, use a gameshark to unlock everything and give max JP. Not really a challenge playthrough (though gold management is a pain), but enjoyable.
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No amount of planning will ever replace dumb luck.