Re: where do so many tenses come from?

Nathan Sanders wrote:

Simplifying one aspect of the grammar causes complexity elsewhere.
For example, reducing the number of morphological case markers
increases potential ambiguity (is John eating the lion, or vice versa?
Is that German bee flying over the fence to the other side, or is it
merely hovering above it?), and thus, requires extra words
(prepositions, adverbial phrases or other circumlocutions, etc.) or
stricter rules on word order to achieve the same level of
distinctiveness achieved by (simply?) having multiple cases.

But couldn't you measure regularity? Expressing a grammatical feature
by one means only should not decrease distinctiveness, yet increase
simplicity. What is gained by having eg. several plural forms?

Regards
Oliver

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