I like what was done to the crabmen variety.
Let say that there are still 4 types / their stats in BB2:
Brawler (pincer+shield) / 11 HP, 2 armour
Grenadier (pincer+grenade) / 11 HP, 1 armour
Gunner (gun+grenade) / 10 HP, 1 armour
Tank (gun+shield) / 15 HP, 2 armour
But now all of them can have normal or better “spitter head”, they can or cannot have carapace (actually it is better for them to have it), or can have heavy (more hp and armour) or agile legs (more move).
Before BB3 it was quite easy to deal with them. Brawlers were loosing their legs, Gunners were overall easy to kill, Grenadiers were something between Brawler and Gunner, and only Tanks were tougher, but you could destroy their gun and they became useless.
Right now all of them lost some HP as all will vary between 6 - 12, but all of them could become more armoured making them more tougher (average of almost 2 armour everywhere, except small head and arms). Their gun now has more HP so it is not so easy to remove it (1 shot from sniper rifle won’t do that). Carapace also get more resistant so their most exposed to gunfire part won’t get eliminated so fast.
Brawlers and grenadiers with heavy legs won’t be stopped so easily, gunners with carapace will bounce some of your fire, and tanks have more resistant gun.
For me now the most feared variant is armoured gunner: machine gun + grenade + spitter head + carapace + heavy legs. Quite many armour and HP, with exception that their grenade arm is their weakness in armour, but if they will surround you and will start shooting with those grenades then you are screwed. And every one of them will return fire with their gun in your turn.