Well... Yes it was.
You could finish all the missions without using it a single time, actually the developers intented for you to not spam blink and and the game gives you a proper challenge if you don't use it.
And you can say the same about Focus in the new Thief. Doesn't mean the game wasn't entirely designed around it, because it was. I never said it was mandatory, I said the game was designed with it in mind. They may have changed it "pretty far" into development, but they also said it wasn't too far to change a bunch of things about the game to suit the fact that you start with the Blink power.
Blink is there so people that don't have patience for a stealth game can play, well, at least it is useful to speed up a replay.
Well given that Dishonored was never meant to be a new Thief and was never meant to be a pure stealth game like Thief, it sounds like you're just complaining that they made a game you didn't care for rather than complaining about any actual issue with the gameplay.
Combat on Deus Ex was shit, it was the least enjoyable aspect of it, what made it great was the level design and the way the augmentations interacted with it and some choices you could make along the way much like Dishonored already. There wasn't any motivation to avoid combat in Deus Ex, the main motivation for me was to avoid that clunky shit but enemies weren't challenging. What Dishonored needs are two things, more tools for stealth (combat is fine as it is in terms of tools) and enemies that can resist or have the same powers as you so it doesn't become a power raping orgy for people that like combat.
It was clunky but it gave you many ways to approach it from an inventory standpoint, as opposed to Dishonored where you get a knife.
But in other words, yes, they just decided to make a game you didn't agree with and instead of accepting that you're claiming the conscious choices they made in designing an action stealth game were somehow detrimental decisions getting in the way of the "true game" which you believe is a stealth game. But it wasn't. They made the kind of game they wanted to make, which was an action stealth game. The stealth was more comprehensive than the combat, which is why the combat could do with some fleshing out, to strike a balance between playstyles, something that they were planning the whole time. More variety on the player's end can lead to more variety on the enemy's end, and there's no reason that in a game being hyped up for having different playstyles we should be stuck using a knife for direct combat.
Arkane made their name doing first-person melee combat better than anybody else, and it's a joke that we got a game with first-person melee combat but little to nothing of what made their previous games so great remaining in the system. More options is better. More combat options will make better combat, and Arkane absolutely knows how to make it work.
I'm basing all of this on what the game was "supposed" to be in accordance with the things they said in development, and the mechanics that were in the final game. I supposed we could always blame Bethesda for the game being action/stealth rather than just a stealth game, but the guys at Arkane seemed genuinely enthusiastic and passionate about every part of the game, and there's no way for us to know otherwise.