Since there are no exceptions in Esperanto, it would be mega cool if there was a sentence builder.

For example, the interface might be like this:

click to add subject --> John
click to add verb --> legas
click to add adverb --> rapide
click to add subject --> libron
click to add preposition -->
click to add time -->
click to add clause -->
click to add conjunction -->

Result:
John rapide legas libron

The program should be able to identify many different styles of sentences. The program should accept many words and put it together in a nice, neat sentence.

I might end up doing a meta analyse of some Esperanto works to find the most common word orders and structures.

Alkanadi:Since there are no exceptions in Esperanto

There are no exceptions in Esperanto at Fundamento level.
Rules not from Fundamento can have and often have exceptions.
So your sentence builder can construct simle sentences only.