I think that the RC5 was made perfectly.
Why would you need the RC5/ESEE5 in a .20 or.188 thickness when you have the RC4 RC3 and RC6? The RC5 was built as an a$$ kicking, tough as nails/pry open nuclear silo doors knife....It is the perfect hard use knife.
It wasnt intended as a bushcraft knife..thats what the RC3 and RC4 are for.It was intended to be jack of all trades , master of none.
If SH*T ever hit the fan, you would be thankful for the extra girth on the RC5 if you had one..its like having cash in the bank to spend.. you may not need to use it, but its there if you need it
I use thick knives all the time, i apply learning bushcraft skills with them even though that isnt thier intended purpose....YES it is easier to make a featherstick with a RC3,4 or6...but practice makes perfect, and anything i can do with my RC4 i can do with my RC5.
If i had ANY say in it, i wouldnt make an RC5 in a thinner version.
You dont like the 5? buy somthing else. The 5 is purpose built...and it fulfills that purpose well.