Copy/paste will be great, from macros to talking past language barriers and more. I look forward to it being implemented.
For auto-translate, can we get a website that lists all the phrases in each language and the phrases you've posted on the FFXI website too? When we get copy/paste we can use this to augment the limited auto-translate dictionary, as well as use older terms that might get removed.
Another feature that would be a nice bonus would be auto-translate for the forums! It would be a nice testbed of phrases, and it would be a bit more fun then tagging things with Seagreen/Red tags to try to make it look like Auto-Translate. I think this might not be completely possible, but if it is, it would be great.
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While the L1 button isn't particularly something I care for, the ×, ○, □, △ button translate has been long useful for making symbols, so make sure that is enterable via an ALT code for non-PC platforms, or at very least copy/pastable if you are removing it. I wouldn't say they're as important to FFXI's culture as certain other autotranslate phrases however.
Widescan would be another nice one to see, it doesn't seem to be in the game for some reason. It isn't high priority though, it isn't something widely said.