It would be preferable if they were "gooses" and "mooses." The Latin -us to -i in plural forms should also be discarded, and replaced with a simple addition of "es." The "fish" plural "fish" should be discarded in favor of the "fishes" variant. The plural of "mouse" should be "mouses" rather than "mice." Those are the only strange plurals I can think of off the top of my head.
That just sounds funny. I have two pet fishes and they have two pet mouses.
I have always thought that English was an easy language for foreigners to learn without all the declensions of many other languages, such as German for instance. OK English is full of irregularities and inconsistencies but with practice all these should become sort of second nature and all the examples Adam listed make sense in the end. I always thought that the horror of the -OUGH endings would be difficult for learners to master with the various pronunciations. I was on a train not so long ago and we pulled into Slough station, and some Germans behind me thought they were in SLUFF. Cheers!
Plurals....another sort of inconsistency in English. Fishes can be used as the plural of fish, but fish is the one used mostly. To me personally fishes sounds strange except when used as a verb.