Sharp, but too bulky and heavy

I started (don't know if anyone will remember) initially moaning really badly about the how I thought the 18-55 F2.8-4 OIS LM was awful etc etc.

6 months later I'm of the opinion it's fab

Only reason I'd opt for the 16-55 would be if I needed 16mm or constant F2.8 or WR or all three

That's literally it.

The 18-55 is sharp throughout the range to a high degree. at 23mm is still F3.2 and stays there until F3.6 at aprox 30mm.

It doesn't become F4 until aprox 40mm.

No CA issues and distortion is handled so well in camera and post I conclude there barely is any I ever notice!

My X-T2 HIGH ISO performance is really good. So a quarter or half stop to 40mm and with OIS mutes any real world difference really and at 40-50mm all we're talking about is small bokeh differences. and one stop of light

Any other differences will be only really noticed by pixel peeping not in print IMO

That's just my subjective take on why I am not tempted by the 16-55. And when I shot Nikon I did use a 17-50mm F2.8 as it really was a HUGE step up in IQ and AF speed from the kit lens.

I know now why the 18-55 is not a cheap lens. At 18mm I find it as sharp or better than the 18mm F2. At 23mm it's pixel peeping differences between my 23mm F2.

I must state I'm primarily street and documentary. So I keep the 23mm F2 as an all day low light option and as I love the light weight and size for street photography where I have always and still do use only 35mm 135 eqvt FL.  And I love SP and I want my work to have peach IQ which the 23mm delivers.  It is real prime time peachy   Otherwise I would not need it and if I shot other FL's I'd use the 18-55 in all honesty.

Now

I also do what I call B&W 'bistro / coffee shop prints' - stuff I do at famous places like St Pauls cathedral or if I'm in Rome the Colosseum etc to eventually try to sell to get up on walls of commercial properties or web print sales also etc.

I actually though that I'd buy the 16-55 for those. I went out and did a day in London at St Paul's, London Bridge and the London Eye and was eating my hat on here apologising for my previous bad mouthing of the 18-55 as I realised the IQ was good enough for commercial print quality! (In my opinion YMM and, my photos are not edge to edge perfect landscapes where anyone may be looking at tiny foliage detail in the extreme corners ha ha)

I am not denying that the 23mm F2 doesn't have way sharper edges and corners as it really really does!   If you want well resolved roof tiles and foliage in the corners blow up at 100% this is not the lens.   And the 23mm F2 had just slightly sharper and better resolved center also. And thus by extension so would the 16-55 as reviews suggest.

But I only notice it at 100% not at say 30cm x 50cm print sizes at 300dpi or 60cm x 40cm at 250 dpi as much.  In fact at those print sizes for my purposes, it is barely noticeable unless you were going face up to the print and deliberately looking for corner detail - and I don't make those kind of photos nor find that the majority of people in the world view them in that way

So I hope I provided a good rationale and gave my use case scenario to make it specific to me and that I'm not generalising.