There's lots of ways to get silent assassin in this new series, but I feel like suit only is what you're talking about now. There's really only a few routes to do it, sometimes only one route, because the levels are so designed around changing outfits. I don't even really enjoy suit only, because it's so restrictive.
There is a lot (and I mean,
a lot) of ways to get Silent Assassin in every game in the series (except Codename 47 for obvious reasons); aside from the obvious ones, there are the not-so-obvious ones, and then there are ones that border on complete insanity.
Many of the ones in the latter category are speedruns. I think it's a happy accident, but the games have been historically rather flexible in that regard; it's just that the less patient player who just wants to get a good rating will likely only see the most "obvious" ways to kill.
Suit Only is also an interesting case because it wasn't formally a challenge until Hitman: Absolution; levels in the series weren't designed with the idea that anyone might do them SO until it became an achievement. Again, this is something that arose from the community challenging itself; Nu-Hitman, for what it's worth, gives you a lot more tools to complete a Suit Only challenge than the previous games while also not allowing for certain abuses of Hitman Blood Money (in HBM, your "Suit" is not a disguise and thus cannot blow your cover, which leads to hilarious Silent Assassin runs where everyone shoots you).
With that in mind, I see no problem with Suit Only being what it always was - a more hardcore challenge for people who enjoy tinkering with the system. That said, now it's not self-imposed. There's a handful of levels in the original games that are downright impossible to stealthily do Suit Only or where the approach relies on flagrant AI abuse and arcane shenaniganry. Nu-Hitman does at least give a Suit Only enthusiast some outing.
I do assure you that my experience with people who play these games dictates that there is a very hardcore niche group of people who know the mechanics well enough to invent SO strategies you and I wouldn't have ever figured out on our own. You're welcome not to enjoy Suit Only, or even gunning for Silent Assassin, and that's always been the case - I have a friend who only ever played the original Hitman 2 (from 2002) as a quasi-ninja favoring a silenced sub-machine gun and simply shot everyone who was a risk to his disguise. The game is generally fairly open-ended; it can be played as an assassin simulator and a
The Incredible Machine spinoff all the same. You can complete it once in 5 hours or spend hundreds on just having fun with dumb shit.