Higher gH water isn't a problem for most plants, it is a measure of magnesium and calcium in the water. As li_gagnyi mentioned, at reasonable levels it is good for their growth. So its no issue for plants.
Hard water is only an issue for certain fishes and shrimps, those that are okay in hard water or a wide range of parameter will have no problems, but those fishes and shrimps that specifically need softer water are the ones which may encounter problems. If you are planning to keep those soft water specific fishes and shrimps, then you'll need to adjust the tank parameters.
I guess its a matter of either choosing suitable fauna to fit existing tank conditions, or designing the tank to suit specific fauna.

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