After years of dealing with Graduate student missteps and ROOT->Java interoperability, to me, ROOT will always mean: blown stacks (i.e. double hist_data[1000000];), poor documentation on TTree/TBranch, NPEs, exceptions, the horrible bag of "features" TObject is, terrible debug statements, no logging, GUI hell, pseudo-.C-macro-compilation-that-only-works-with-trivial-cases, code translation, dlopen madness, code interoprability, Mac OSX support, 2+ hour compilations, TList hell because no STL (NO STL!?!?!), etc...

Years of physicists time has been wasted on CINT, and many more years on ROOT itself.

I'm sure Cling is much better, and it looks cool on it's own, but I know ROOT isn't. Luckily I only have to dig in the source code for ROOT once a year or so (the last time was figuring out they finally got around to adding LZMA compression to ROOT files when things started breaking at work).

I used to think PyRoot was the way forward. Eventually, ROOT will be burned at the stake and everyone will over with Julia.

Why would the semantics change if you use an interpreter rather than a compiler?