Agi doesn't need a buff, you just need to put some points into str. This is a fighting game, not racing game. You have to be able to hit and do some damage so why shouldn't you have some strength? You can use nearly the heaviest armour with just 15 str and still run rings around people with lighter gear. If anything armour needs a higher str requirement and possibly 3 agi chars should have more downsides like slower swing speed
Phase has 15 str , 24 agi , he kills everyone , he's fast , and he hit very hard because of his speed. No, agi and strengh are quite balanced if you know how play with your build.
Str = stronk , hit very hard with like 24/27 , may not be too slow with 12 agi at least
Agi = fast , but no HP , a lot of WM and speed which help you to do high damages.
each thing has its qualities and defaults , deal with it , in the life , you have to make choices . Don't complain about agi is too weak .