...
Meanwhile, TClonesArrays have evolved tsuch that they can contain objects that allocate memory. Without this restriction, we could modify our ROOT structures to use TClonesArrays in all cases and ditch TObjArrays once and for all. This affects MC, Digi, and Recon...so changes would involve mcRootData, digiRootData, reconRootData.
Then the question is do we require backward compatibility such that current ROOT files need to be readable by the new versions of the xxxRootData packages? Possible, just a bit more messy..