I can't seem to shake the feeling that the ai for the human grunts and the combine soldiers is not as dynamic when compared to their original counterparts, and I feel that a comparison between the two would demonstrate this best. I don't have recording software installed so I have arranged a reproducible test and some screenshots instead.

I have set up 4 standard grunts in front of 4 headcrabs

https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=2614956282
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=2614956448

upon enabling their ai, the grunts immediately ran for cover or just put some distance between themselves and the headcrabs.

https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=2614957245

this movement continued for the duration of the fight and most of the npcs ended up in a different position after the fight than when they started

https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=2614957374

Now compare this to this pack's human grunts:

https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=2614957746

they stood in place, shot/blew up (really like that they can use the grenade launcher btw, good adition) the headcrabs and wandered off after the fight.

When the two are compared, I personally found the HL:S grunts more entertaining to watch than the Resurgence ones, and this feeling carries over to fighting with them as well. In said fights I often find that the soldiers maneuver behind me as if they were attempting to flank me, and will throw grenades more often, forcing me to move and changing the current combat situation slightly. This generally makes the enemy feel more lively in combat, as it seems that they are actively responding to me in fights. I find this feeling of reactivity in my video game enemies to be one of the most enjoyable parts of fighting them, and is something that I found these npcs (and many "standard" VJ base npcs if I recall correctly) lacked. I'm not sure exactly how this is achieved, as I have never programmed ai before, but perhaps you could look to the original code of these npcs and maybe emulate some of it's techniques. My apologies if this was something already under consideration by you, but I wanted to bring my opinion on this to light in hopes that considering it would improve this addon substantially. additional apologies for the wordiness of this post.

TL;DR: I think the npcs should move around more like they did in the games, it's more fun when they do that. sorry this was so long, I was hoping the cringe-lords from the other threads would avoid this on account of their presumably short attention spans.