I'm not sure there's much of anything you can do to make the Blade less powerful and still capable of reaching the Wormhole. At the same time, if you buff the non-HW anti-Blade Exowaves to the point they can threaten the Blade, there's nothing else in the game that could even slow those Exos down.
If that's the case, then the exos should behave like normal exos, ie pick a random irreplaceable and go for it.
Or nerf both the exos and blade.
I'd be inclined to say do both if you find the blade to be to strong, I don't think it is for what it has to deal with though.
The problem with doing both though is that it sort of ruins the flavor of the Balde. Its supposed to be something amazingly threatening that the AI is scared of.
Also, the waves need to be small enough that defenses without your fleet (and the blade) can take them, since the entire point is to bring the blade to the AI homeworld you can't leave it home to defend, and the homeworld waves are hilariously strong at this point (those probably need nerfing, right now game winning fleets that could sweep the AI homeworld with little to no losses, and then go do the same to the other one, get simply munched trying to get the blade into position.) so you will need everything that moves to get the thing into position, if its possible at all.
Somebody mentioned his full Spire fleet couldn't do the job, that's more than a little scary, since I've yet to meet anything that could seriously challenge my Spire fleets that didn't also seriously challenge my CPU.
My blade game doesn't include spire, but I'm still getting nowhere after several attempts. I've got a couple of ideas left, but I'm down to "Weeeell it might work?" ideas.
If the exo's did go for things other than the Blade I think it'd be quite doable, you could distract them while the Blade circles wide, but since they always go right for it you are always forced to run right into the guns of everything, on the other hand if those massive exo's get away you had better win soon cause I suspect they'll crush just about anything they wander up to.