If all rational, logical, philosophical, scientific, and mathematical reasoning starts with the initial axiom that 'X=X' - that is a 0 information tautology - can it be said that all ensuing rational, etc statements are therefore empty of any Essential truth and only nominal?
'Identity' has several shades of meaning. 'X = X' does seem particularly vacuous. But if you translate identity to some perfectly ordinary contexts, it proves a useful concept.
Diachronic identity - identity over time. If I am the same person now who defrauded a client a year ago, then I now am responsible for what I did a year ago. I am the same person, after all : I am not someone else, e.g. you. Without X = X (GT at time 2 = GT at time 1) by legal criteria, personal responsibility for past actions would not hold. It might be convenient if it didn't !
'By legal criteria' : this brings out an important point. There is no single set of criteria by which to apply X = X. By biological criteria I might not be identical now to myself a year ago : pretty certainly I am not. This suggests the familiar point that identity is relative to a description. Not everyone accepts this thesis of Peter Geach's but I do. Suppose (an unoriginal example) I bought a clay statue last year, a statue of John F. Kennedy. I change my political attitudes and remould it into a statue of Richard Nixon. For all practical purposes, it is the same clay and it is important to insist on this. 'Of course, it's the same clay', I say : X = X. (X at time2 = X at time1 as above). But I can also say, 'Yes, I now have a different statue'. If I simply say, 'I have a different statue' this leaves out the X = X factor, the fact that it is the same clay differently configured.
X = X is empty out of context. In context - the context of diachronic or relative identity - it is informative.