It's ironic to see everyone objecting to Large size on this thread as extremely powerful, when in the general case, if you comment on how e.g. Mounted Combatant is a very strong feat, so many people will turn right around and tell you that you can't get Large-sized mounts into adventuring locations like dungeons and that Mounted Combatant is therefore useless. Both of these things cannot be true simultaneously.
I'm not saying it's the same people speaking up in both cases BTW, just that it's interesting to see.
Speaking for myself, I'm fine with Large PCs. It has advantages (larger weapons) and disadvantages (harder to get cover; penalties from fighting in smaller spaces), plus the intrinsic disadvantages of being a ranger instead of a fighter (fewer attacks) and the Guardian form itself (low mobility).
But then, I grew up with 2nd edition Dark Sun, so half-giants aren't a new thing for me.