This is a really nice review. And I mean nice in a way that it paints a very rosy picture of what in my view is one of the worst airports in the region. As a regular guest to T4 of KWI I find everything to be average. Nothing is special, nobody seems to care and when I read that T4 opened only in 2018 I can't believe it; it really is worn or not built in good quality (or both). It will be interesting to see whether their new terminal which will open in a number of years (certainly not any time soon) will be any better.
Admittedly, I have not been landsite at T4 and also not been to the First Class Lounge. The only positive I can say about T4: The lounges are usually not crowded. And certainly T4 is the best terminal in KWI.
If you go to T1 everything is much worse. Nothing is average - because everything is bad at T1! One of the most horrible terminals in the world I have been flying in and out of. It starts with the process of changing terminals airside (avoiding immigration) in KWI which is a mess! Security when you leave the terminal, undefined wait for a bus to the other terminal (sometimes 5 mins, sometimes an hour), again security when you enter the other terminal (after an airside busride via the apron) and especially in T1 extremely awful hardware in every respect.
I know how most of us here (dis)like the LH product. But after changing in KWI you actually feel very comfortable getting onto a LH plane with the seats which replacement is 7 years overdue.
(As of next week QR is serving my regular destination - bye bye KWI, KU - and to some extent LH)