I came here to look if there is something about this and totally agree there should be casual duos instead and here is why;
I have played hundred of casual squad matches and tbh its more enjoyable than full human controlled redsec, but like you mentioned, over 50% of players are very bad, leave before match start or right after first death etc. Very often when I land top 10 its just me and if lucky 2-3 others left. There should be also some matchmaking system so pros (=streamers) cant join. Its called casual for reason. Amongst the bots if we start having 8:1 k/kd players it kinda takes away the fun.
ps. Invest also other casual options. I tried normal breakthrough and conquest and no, its not fun. People camping with helis killing everything. Also feels like its cheat infested all the way. Rank 1-50 players are hitting only headshots. Reported possibly hundred of cheaters so far and received maybe 3 emails that action have taken against. Also spectate would help with casual because people use by reason naming its impossible to write down.