Extra orders would be nice. I would especially like to see the Repair order from AT to help Titans repair themselves. Cleaned up building rules would be nice too.

If we want to make the "Repair" order more attractive, it could allow one damaged location to be automatically repaired, no roll needed. Each location after the first that needs to be repaired is slightly less likely, the second needing a 2+ (on 1d6), the third needing 3+, etc. The sixth and any subsequent locations would repair at 6+. The owner of the model chooses what order to repair things in. This includes Shields, at one Shield per position.

As a clarification on Repair, how would the order affect the model's ability to fight in Close Combat? Obviously it cannot start one, but if it gets charged that turn it should probably be nearly defenseless.

There's already a large disparity between Titans and everything else so I'm not so keen on limiting vehicles further to simply hitting the bottom leg location. I always imagine that when vehicles assault a Titan they are more likely to cause damage to the Titan with their weapons than they are by slamming into the Titan's foot. Same goes for infantry. Although strictly you are use CAF and not weapons, I would always imagine that a Devastator detachment got a lucky missile through to cause damage and this therefore could be anywhere on the side of the Titan they are facing.

I still prefer half CAF.