OK, question!! If I just take the crit path, my char should not develop as far in say 30 hours as a char who attempts all the side quests for say 80 hours. Now, here's the question- what will be the difference in experience for me and/or my char by the end game? Will the final 'boss' battle be too easy because I'm now a much higher level, or would it have been too hard at the lower level? I'm hoping it won't be similar to another unmentioned game, where you could complete everything at level 1 if you so chose!! What's the trade off the company is considering? Thanks!!
As I understand it, it varies from game to game. Some games have a "It's as hard as it is" philosophy (I believe Hordes was like this), where if you do all the side content, the end bosses are a fair bit easier than if you get there as fast as you can.
Other games have total scaling, so yeah, like in Oblivion, the arena is just as hard at level 20 as at level 5.
In Jade, frankly, there isn't enough side content to change things much one way or the other. You're gonna be somewhere in the 20s when you finish the game, unless you do something crazy like go to the ghost-spawning points with your most-XP-for-ghosts amulet on and whack ghosts for 100 hours. You're welcome to do that, and you'll be, uh, much higher. In Jade, it wasn't even that much of a deal, because by level 20, you'd already max'd out the martial style you wanted, the support style you wanted, and either the magic or transformation style you wanted, based on points spent. So any points beyond that point were just to broaden your horizons... and the extra health or chi is pretty minor in the last fight, all things considered.
The in-between point I like is graduated scaling, where, to use D&D as an example, if you do the end boss at level 10, he's level 15, but if you do him at level 15, he's only level 18. He scales up, but you still get a reward for doing the side stuff.
(And let's be honest here. Your reward for doing the side stuff isn't really "being able to finish the game". If that's the reward, then it's not really side stuff. It's critpath stuff of which you have to do a certain amount. The reward for doing side quests is exploring the world, getting a few more hours' worth of entertainment, and maybe running into some challenges that weren't appropriate for the critpath (too hard, too niche as far as puzzles go, too touchy a subject for a critpath roleplaying plot). So our side quests are never gonna give rewards as good as in the critpath -- and I think that's a good thing. If they did, they'd be effectively critpath, and then in short order they WOULD be critpath, so that nobody would miss them and not be able to finish the game.)