I've seen guys on the trail trying the welded front axle and only locking one hub. This is also the same effect as guys with any true locker in the front and breaking a shaft or joint on one side and continuing on the trail without repairs (I've done this myself a few times). It does NOT act like a selectable locker. You have 100% of the power always going to one side on the front in this situation which can lead to some weird handling (obviously pulling to that side). That side with the hub locked will also be spinning if you put all of the weight on it, or all of the traction, versus an open diff in which the side with the least amount of traction will spin. This last comment would also mean that a welded front diff with one hub locked would be harder on shafts and joints because you would 100% of the power going to it all of the time instead of splitting it side to side like a locker.
Overall I did not like running my truck that way simply because of the constant pulling and it just felt weird when going through obstacles. It was also somewhat funny watching the guys with welded diffs try the "one hub unlocked" thing and somebody constantly jumping out to lock the hub in, or getting hung up on something "they didn't think they would need the front locked"......entertaining when it's on the middle of hill or in some mud.
For the steering aspect in regards to X-over, hydro, etc..., I think most people kind of get confused to what is going on. X-over is not going to overcome the effects of a welded front diff, it only helps when the vehicle is flexed out and would cause draglink geometry issues with the stock short draglink. On the trail when you really need steering control you are either going real slow or stopped......a welded front diff isn't going to make much of a difference, especially if you are stopped......you can either turn the tires or you can't. Hydro assist may help you physically turn the tires in one direction, but the true issue with a welded front is that the vehicle simply does not want to turn very sharp because of all of the scrub the tires see....the tires are turned but the whole vehicle just slides straight ahead. I can definitely see why people like hydro assist and think it helps with a welded front diff, but that's because you have to move the steering wheel more, or do 3-point turns, to get around with a welded front diff, but hydro is not overcoming the effects of the welded diff but only making it easier to live with.
I wouldn't have thought of that on my oun 
. Eventually when my wife quits making me spend $$ one verything but I am going selectable lockers front and rear. If you do weld it up I suggest putting an inline cooler on, your fluid gets hot and boils over, atleast thats what happened to me (twice).
