Why? Give me reasons, man... opinions are subjective...
The Aqua V1 is a PITA. The Fogger before V4 were hard to build. The GG RTAs are simply STUPID with the need for nr-r-nr wires... the Lemo 2 is better than all of those.
My wife won't vape anything but a Lemo 2...she has 3 of them now. Like the original Lemo, the flavor is excellent with a decent build in it. In fact, the Lemo/Lemo 2 have managed to hold their own flavor-wise against any of my latest outbreaks of shinyitis....and above all, I'm pretty damn picky about flavor production.
I think it's biggest flaw is that they gave it to more airflow then this particular style of tank can use and still wick effectively. IMO, wide open, there isn't enough vacuum being created to effectively draw thicker liquids. As my wife vapes, (an airy MTL, using 50/50 liquids), it performs beautifully.
The chimney size isn't a concern. It's interchangeable with the OG Lemo which is also known for it's excellent flavor. I believe the larger ID of the chimney top was a structural consideration. The top cap screws to the chimney top as a means to secure the glass tube.