If I were BMW I would put in LCI new iDrive, Laser lights, and maybe tune up a little interior - switching to USB C, steering wheel like in X5 etc. However I do not regret taking pre LCI model. I can enjoy it now, and when you pick LCI model you are counting the time till next model will come, so there is no good choice. If you like what is currently on sales just take it and enjoy!
Especially in M5 where we have engine from the previous generation so In my opinion it is really refined.