Well obviously in the current system there couldn't be UNLIMITED subsitutions since there are ONLY ５ adavanced instructions, but yeah, 5 will be nicer.I have been asking for "unlimited" substitutions during friendly matches for almost 2 seasons now.
I hope it is something developers are working to address 
That is why I put "unlimited" in quotes. Of course the number of substitutions possible in a match depends on the number of advance instructions but these could change drastically in the future. For example,
one thing I hope to eventually see is the ability to make multiple substitutions with one advance instruction, a change that may be easier to implement than adding more individual advance instructions. With (up to) 2 substitutions per advance instruction, this would enable up to 10 subs in a friendly match without any additional advance instructions. So instead of making my comment only relevant to the current system as it exists now, I used the word "unlimited" instead of "five".
