Little Shop of Horrors is a fun movie, play and musical.
I just watched the 1986 version again and really enjoyed it. it has great casting, some really great songs and some really cool practical effects. these days Audey II would be all cg and not be nearly as much fun.
besides, how realistic would a talking plant be?
I watched the unused ending on youtube and it looked pretty cool as well. far more in keeping with the play and the original movie, but lots of destruction. some definite nods to Godzilla in there as well as several other giant monster movies.
but really, they didn't think of using fire on the plants? or napalm? we all know alien plants can be burnt to a crisp using electricity as well...