Alright, here's a discussion that just started on the wiki, that could use some discussion before anyone goes fixing things. A quick summary:
Character's Pokémon are named "Character's Pokémon" in English; for example, "Ash's Bulbasaur".
In the Japanese translation/romanization, we keep the same format. "Ash's Bulbasaur" becomes "Satoshi's Fushigidane". The problem? The Japanese language doesn't pluralize or use possessives like the English language, i.e., there's no "s" to signify a plural. "Satoshi no Fushigidane" would be the correct translation. "Bulbizarre de Ash" would be proper French.
There is, of course, a counter-argument to this. For one, it's a romanization of the language, on an English website, so simplifying things to cater to English readers is a minor benefit. I personally am biased towards the correct translations, seeing as we aim to correctly document Pokémon; that should extend to documenting other-language titles correctly as well, if at all.
*Correct translations would be more helpful to users who wanted to see exactly how Ash's Bulbasaur is named in Japanese (or other languages).
*The English-possessive translations teach users the wrong names for trainer's Pokémon, while not indicating that there's anything different about them.
*Changing every other-language title on the wiki would be a large job. A very large job (not only would trainer's Pokémon need changing, but also TCG cards of trainer's Pokémon).
*Translations might require users with foreknowledge of the languages in question, research for the cards in other languages to get the titles right, and more hard work.
I'm sure more pros or cons could be thought up, but I'm drawing a blank right now. (I'll add more to the list as people suggest them, if the discussion goes on that far.)
:EDIT: The poll might seem a bit confusing; I messed up a bit on the grammar when I made it, and I don't think I can edit it. "Yes" means in favor of, and "No" means against. I should have read it through before I submitted...
:EDIT 2: Yes, yes. As many people have pointed out, I mixed up "Plural" and "Possessive". Fixed.