I was just reviewing the specializations from the EotE core the other day and came to many of the same conclusions you did. I took a stab at changing the Bodyguard which I felt, given its namesake, could be a little better at "bodyguarding". I ended up removing the Gunnery from the skill list and replacing it with Vigilance. I removed all ranks of Barrage, replacing them with two ranks in Keen Eyed and Bodyguard (Supreme). Overall, I felt spotting threats and searching environments fit more with my idea of a bodyguard than being able to use vehicle weapons at long ranges.