It's not newer vs older. It's slick hipster-looking mac-like all-soldered X series vs thicker corporate all-serviceable bricks of T series. (I greatly prefer the latter, of course.)

My understanding is that the newer X- and T- are still less serviceable than earlier models in the same line.

I don't know how much more servicable the older models were, but the newer models come with an instruction manual that explains how to replace most of the parts. Unfortunately, the screen is not included in this list. But Youtube has you covered there. My only complaint after repairing my own thinkpad is that the body material is a bit flimpsy and the clips will break after being opened several times.