you know welling on a straight melee charc is going to be pretty tough? unless you make it a hybrid healer or something with a good amount of lifesteal?
i always like going stat plates for arena, but havent tried it with a welling melee character, if you can get a little EE with some stats on it
Yes 100ish dex is very important, it will allow you to crit and protect against getting critted
I would only add more vit if you get good tank amors, I wouldn't want to loose killing power with more stats into vit.
Like I said Ive never tried a straight melee weller, but this is my advice to you, so maybe some1 else who has done this will be able to help you further