the only time i've had a rpoblem with "too many plants" is when they grow in a tangle that makes certain parts of the tank inaccessible to the fish. other than that, if you have a lot of plants you may need to fertilise (fish poop can only go so far) but that's the only complication i can think of.
oh wait, make sure the tall/surface plants don't block light to the shorter ones!
So remember, when you're feeling very small and insecure,
How amazingly unlikely is your birth,
And pray that there's intelligent life somewhere up in space,
'Cause there's bugger-all down here on Earth.
Loki/Grendel/Gail/Beowulf/Camilla/River/Bathory/Arwen/Lafayette/Deb/Jack Skellington (soon)