Cold Star is pretty neat for Strange. The best thing about it is if you do a close st.M+Cold Star, canceled into Mystic Sword M, it will be safe on block against everyone, even crouchers, and will be a true blockstring no matter if they pushblock or not. You get at least a whole second of frame advantage, and even have time to teleport behind and lay an Eye for chip damage, or any other kind of setup.
The THC is broke too, you can probably get some neat extensions off of a raw THC using some OTG flames.
Strange’s high/low mixups depend heavily on assists, because an opponent needs to be held in place for an extended period of time. Cold Star can do this, but since it’s not as fast as Jam Session it might be harder to set up. Basically, after you get someone to block an assist, activate flight mode, move down-forward until you’re low to the ground as possible in flight mode. Strange’s flight goes so low, that if you unfly you will immediately land. If you want to go high, do j.MMH palm, unfly. If you want to go low, immediately unfly and do a cr.H, palm, mystic sword L. You can unfly any of the overheads and go low to make it even harder to block. Again, you need high blockstun assists for this to be viable. Cold Star can work, but it’s just not as quick to come out.
The other problem with Cold Star is it has a lot of assist recovery. As in, once the last active frame is gone, the time it takes for Ammy to leave, and your other assist to become available. Strictly speaking, it’s not that much different from other assists, but with other long range projectile assists like Zero’s, if the projectiles hit late, you still get the frame advantage while your assists are recovering.
But anyway. The fact that you can combo after st.M->Mystic Sword M by calling Cold Star is in itself a good reason to use it. The amount of time you get to combo after it (with a crumple combo even!) and the amount of frame advantage from a blocked cold star, is very useful. And again, the THC is scary, and serves not only as a panic button, but a completely-regain-control button. You can even do more high/lows with it against incoming characters.
So yeah, Strange with Cold Star can work. But the lack of a long range or neutral game assist is gonna make things difficult. So take a beam or missiles with you, or something similar.