As discussed on the mailing list, it would be better if the tika-parsers dependency (and all the parser libraries it pulls in transitively) was included in our deployment packages but not directly in jackrabbit-core. This would make it easier for people to set up custom lightweight deployments with no or only partial full text extraction functionality.
To do this we'll first need to wait for Tika 0.9, as we currently have a custom PDFParser class in jackrabbit-core as a workaround to a problem in Tika 0.8.
At the same time we should do a more thorough review of the transitive parser dependencies we include. At least the rome and bouncycastle libraries were flagged as potentially unnecessary.