I think people are underestimating the cancel. It allows you to hit confirm safely with the threat of a plus 20 on hit move if they challenge the stance. If they dont challenge you dont completely lose your position on screen like you do in reborn.
Yeah, if misery blade remains the same as it is now, the fact that you can end select strings (most importantly B1,4 and F4,2) on either cancel or just enter stance and finish the blockstring with tsuka or delay into it will make his offensive game up close that much better.
Any tsuka hit = jailing for 2,1 or throw or F4,2.
Any of the important strings can be made -2 or -1, depending on timing and opponent and range, without any defensive meter use, and a not easy to react to -2 either, as the animation is very short and blockstun isn't all that high (about 22 frames in total, counting tsuka's startup, active frames and recovery), so if you condition your opponent with cancels and delayed tsukas you'll have a scary stagger game up close, coupled with scorpion's already impressive stagger game at mid distance with B1 and F3.
1,1,Tsuka makes his auto shimmy a lot better, too. Suddenly instead of getting 100dmg and a knockdown out of 1,1,2 you get about half the damage but with a standing reset at +20. On block you're also -2 instead of -6, which makes a world of difference, and you have the threat of cancel > throw at your disposal.
Having a +1 B1,4 instead of returning to long range means you can suddenly change from a very controlled footsies-range game to an up close offensive pressure game out of a hit confirmable mid.
And on top of all that, sin blade adds damage to reborn's damage potential (about 40 extra damage in bnb's) and tsuka makes all enhanced spear standing resets a bit more damaging as well and even more + than with S4 alone.
The remaining misery blade moves are really just extra utility that may end up being useful to close out rounds with a surprising 50/50, even if they're unsafe as all hell.
Only thing that I see hindering this variation is Tsuka's hitbox being inconsistent and matchup dependant after blocked B1,4. From what I've tested, against certain characters (shao Kahn and liu Kang, for example) B1,4,Tsuka won't reach on block at all and against a few others it only seems to reach if you delay Tsuka enough that they stand block it (if they simply hold low block it'll whiff).
I'm hoping this gets looked at and the hitbox is increased ever so slightly that it isn't an issue, but if it remains as is B1,4,Tsuka may not be reliable =/