On my specialist setup I run HL pro then first kill Assassin.
If I spawn and there is a UAV up then thats great because that's the first point I need to get Assassin. I run stinger on all of my Specialist setups for this sole reason.
From whats been said in this thread though I do understand the reasoning for not using HL, it finally made sense to me when Joe explained it.

And where the hell have you been the past week?

I rarely get assists playing hctdm so not having hardline on at the start isn't an issue for me. So thanks to the OP for pointing out the blindingly obvious that I missed.
. You should try this with the striker with damage & extended mags. Once you get the bonus, you have range & speed too. It's insane the range you can kill people at. And you move sooo fast