Since this is a 3 year old post a lot of things has changed for rtl languages like hebrew in Tiki Wiki.
RTL is layout and graphic related (not language translation) and we've got important progress on that side.
Since Tiki 9 we got a better RTL 100% working rtl solution but mono theme (rtl implementation still rely on theme specificity).
Since Tiki 12 we have a complete freedom between theme selection and BiDi (the rtl engine). Meaning each theme can receive is own rtl css addition of styles.
The futur will be Tiki + Bootstrap (first integration for Tiki 13) were rtl will be entirely rebuild using bootstrap.