... fit my hand well, it had night sights, 10 round magazine and was light enough to carry comfortably. What are similar pistols out there that might fit those criteria?
... What am I missing? Is this a niche in the market that does not need filling?
Dunno about "niche", but the smaller 9/.40 guns certainly seem to be selling in greater numbers (outside the predictable 1911 .45 market segment). You often see a lot more interest in the G26/27's than the G30/36's among a lot of folks, for example.
Also, if a 10-rd magazine is firmly on your list of criteria, it can start to restrict your potential choices.
Personally, I own, use and have carried smallish .45's with 3 1/4", 3 1/2" & 3 3/4" barrels. (My larger .45's have 4 1/4", 4 1/2" & 5" barrels)
I don't mind carrying .45's that have 6, 7 or 8-rd mag capacities ... but then I spent some years carrying 6-shot service revolvers, a Colt Commander and a Star PD off-duty.
My M&P 45 uses standard 10-rd mags, which are a bit better than the 7 & 8-rd mags I use in my 1911's, but I'd not be too concerned if I owned & carried a M&P 45 compact that came with 8-rd mags, either.
Matter of fact, my CS45, "original" cutaway grip 4513TSW and Colt OM all came with 6-rd standard capacity mags, making the 7 & 8- mags seem as though they contain an extra margin of capacity.
When it comes right down to it, though, I look at "capacity" as being just one of the factors to consider when selecting an off-duty (and now retirement) weapon, and not necessarily a critical factor, at that. Grip girth, controllability & overall recoil management are of a bit more interest to me, nowadays.
Of course, this is from someone who regularly carries a 5-shot .38 snub or a 6-rd LCP for retirement, too.
Training, practice, skillset, mindset and weapon maintenance/service are all much more important to my needs than sheer capacity (or even caliber, for that matter).
I also tend to like to stay with the major gun companies who either see a lot of LE/Gov business, or at least offer weapons that are commonly approved for optional/personal use by a lot of LE agencies. Reliability and feeding/functioning with modern hollowpoint ammo produced by the major American ammo makers is important to me, too.
You can probably try out a number of potentially interesting smallish .45's that may appeal to you and may fit within
your needs and preferences.