Yeah, the glassing aspect of bear hunting is extremely difficult for the reason you listed: You, for the most part, can't effectively glass concentrations of berries and, with scrub oak, if you are glassing large areas of it, you can't effectively move on a bear in any reasonable amount of time if at all. You look at some of those 35-40 degree scrub oak infested slopes out in Hermosa and you're just not going up that. Its akin to those French hedgerows that would stop Sherman tanks in WWII.
My primary strategy is to glass from high points and ridges. I usually can't actually see (or see much of )the berries themselves, but I can survey the larger area and potentially see bears moving in or out the berries or feeding on scrub oak. In that case, I'm looking for scrub oak with water near, usually a creak in the bottom of the drainage that I also can't see well from that vantage point.
With that strategy, I'm very selective about where I hunt because there just aren't many locations that offer a good glassing perspective. The higher you get, the more you can see ,the longer it takes to move on a bear and they don't tend to stay very still. I like a long ridge in a sea of scrub oak with creeks on both sides: There are berries down at the creek, scrub oak on all S, W and E fasting slopes and a bunch of little nook and cranny subridges you can work your way through. You can't see everything and you have to move a lot, but you can see quite a bit.
Once I burn though that strategy, I'm out in the scrub oak walking up creeks and checking ponds if applicable. Visibility is obviously limited so I'm listening and looking for erratic movement in the scrub oak. Its not my favorite, but it can certainly work.
While bears won't be "far" from water, that doesn't means that they'll be right next to it either. Covering 400,500,600 vertical feet to access water is not a big deal for a bear. While I wouldn't go out of my way to hunt a dry drainage for bear, finding one 2/3rds of the way up a SW facing slope, 400 feet above the creek, is entirely unsurprising. In fact, that's the bear I'm looking for in my primary strategy since I have the greatest likelihood of glassing him up.
I don't claim to be good at it, but I'm definitely getting better at it.