Add 3D variants of the INDEX and MATCH functions
And generally go through all functions and either extend them or make variants such that they work with 2D and 3D ranges better. E.g. why doesn't CONCATENATE do something useful with range arguments.
index(sheet 1:sheet 2!A1,match(A1,sheet 3:sheet 4,0)) would be really handy!!!!
and i'd agree that concatenate seems essentially pointless when "&" does the same job...
I had assumed =concatenate(a1:a100) would be where it came in handy, but that doesn't work either!
Bill Bekenn commented
Interesting idea, but not sure how that would work. Using ranges through the sheets dimension has never been very stable and they are tricky to implement and modify.
I suggest the problem with CONCATENATE() and ranges should be posted separately, that would definitely be useful.