I am not sure if this makes a difference, but I imagine for min maxers it has to.
In EA, there is an item you can get that permanently increases CHA at the cost of 1 INT. And there is another questline that potentially gets you a reward that allows you to choose a stat to increase +1.
Also Question: In EA I am playing a Ranger currently. With Dex at 20, is seems like the difference in AC between medium and light armor is worse les than what I lose from losing the Dex bonus. Is this just due to current itemization options in the game, or in general is it just a bad idea to do high dex builds and medium armor?
Not particularly, depending on how they scale the different armors with magic items you can achieve the same AC with non-magic equipment if you go light armor max dex or medium with 14 dex. The highest medium armor comes with disadvantage to stealth though, so if you go full 20 Dex and studded leather you come out ahead of medium armor. However we don't know if the armor types are going to scale linearly as in each armor gets the same +1, +2, +3s at the same time or if heacy and medium will get higher bonuses.
All that said, you'll probably be fine.
