You are correct the edit time is set to 10 minutes at present.
I have some ideas up my sleeve, and plan to take them to the next Webmaster and Senior Admin meeting.
I have the ability to set it so no-one can delete a topic (first post within a topic), though people can "soft" delete their OWN other posts. Soft delete removes the post from view except for Senior Admins and Webmasters, who will still be able to see it (just in a different colour). This means that should someone post some racist remark or personal attack and then delete it later to cover their tracks, then the Seniors still have evidence should they need it.
I will also propose that the edit time does remain at 10 minutes (maybe up to an hour), for the same reason above, to prevent someone editing a dodgy post at a later date to cover their tracks.
HOWEVER I can make no promises that the Seniors will want any changes done, though I will take this to them as an option to keep all parties happy.
In the meantime I would like to give you some useful tuition. Firstly re-read you post prior to posting. Even use the preview button. Also use the latest version of Firefox (13) which has a built in spell checker, so if you misspell it underlines it in red. You can then right click the word, for the correct spelling.
Also if you started a topic and you believe it's getting out of hand, I would recommend thinking before starting topics that could go south. Alternatively, if you see a post you aren't happy with, please feel free to use the "Report" button below each post of the left. You then have the ability to explain why you want a post removed, etc. This then gets flagged up for the Senior Admins (only) to review, and take the appropriate action.