That's fine - so they are of interest to you because you're interested in linguistics (I assume). Does that mean they should be officially spelled that way too? Just so linguists can have something to discuss? Surely not! Languages are simply a vehicle for expressing thoughts. Their grammar and spelling is a functional, not artistic, part of that system.
Ideally the only acceptable plural of forum would be forums and a dictionary would state "Original Latin plural 'fora' ". This way interested parties could find out the word's history but regular people wouldn't need to know. English is fast becoming the world's lingua franca and it is out of our hands now. We need the lingua franca to be better structured.
As for your desire for English to be better structured, and to have rules to remove all ambiguity regarding plurals (and probably all the other ambiguities too) I think the language has been doing just fine with ambiguity for a good long time now, and will continue to do so. Languages do not become the world's lingua franca because of how wonderfully systematic, unambiguous and regular they are, and if English continues to maintain the requirements for a lingua franca (which are largely political, social and economic rather than linguistic) then a lingua franca it will remain.