Concerning the prodigies, flexible combat is a must, of course.
But why not replace draconic will by either
- arcane might (that will roughly give you +30% melee damage)
- or eye of the tiger (that will give you a double strike every 2 turns, with also approximately +30% damage)
Draconic will can be replaced by a wild infusion and a unique movement infusion should be enough...
I am not 100% sure, but I believe there is some wiggle room here. I am not 100% convinced that Draconic Will is entirely necessary for this build. I think it is probably the most bang for your buck especially if you play the build as roguelike. As Effigy says there are tons of negative effects and in certain very annoying places draconic will really shines even if 90% to time you are ok.
But beyond that, given that this build with the stats enumerated can kill the final bosses before you out of time, do you need more damage?
Secondly both of those increase melee damage. I killed Argoniel (admittedly a special case he may or may not have the crazy armor value) solely with procs from Earthen missile and Arcane might would have had no effect on that. An extra double strike here and there would help but not that much.
In the end my evaluation is the build does enough damage, so being consistently and reliably unimpeded and fast is much more important (especially since that is also a contributor to overall damage and efficiency).
Now you are perfectly able to swap of these around and I think you can even make it work. I just don't think you will see the returns on it.
Eye of the tiger may seem nice as this build has LOTS of crits. But EoT is limited to one per action and in the end the build just doesn't benefit that much as only double strike really gets helped. But EoT may not apply to DS, its random which one it descreses and you have a lot of "noise" from various long CD skills that may get hit instead.
All in all I would say don't do EoT you should (I have not tested it) find it to be quite bad on this build I think. Many things just have too long of a CD to really help much and they will get hit instead. And in the end, unlike a normal brawler, DS is not really a huge thing its just a nice thing that weight unarmed as better than other Magic Combat options. Arcane Might you can try but I don't think it will be noticably better (obviously it must increase some, but the effect will be negligible) such that having complete immunity will be obvious better/more conviennt. I would say that even when Draconic Will is no longer extended by Timeless it will still be a better option.
On a related note it may be possible to repuprose aspects of this build to seriously reduce certain cooldowns via the Meta line and spell CD reduction similar to what Mex does in his Archmage guide. I purposely opted not to do this for two reason:
1) Unstoppable is cheesy enough and I didn't want extra cheese on my pizza
2) if the base idea of the build worked then it was pointless (i.e. kill everything before Unstoppable is out else hide and rest).
So for people who really want to leverage killer CDs on Timeless and getting rid of Draconic Will for something else that may a potential avenue. I would say that such a thing would take precise tuning and some pretty serious thought and testing to make it work out in Madness. While such a variation may only wind up something like 8 class points different it would still be a very significant change gameplay wise, such that I cannot tell you in an reliable way what its performance would be like. However I think its possible and maybe even feasible.
Edit: I think for the above variation EOT may work well, not sure, in that EM procs should consistently reduce spell CDs and you can possibly get Metaflow going pretty regular and get mabye like 20-30% spell reduc on items. Then you can completely get tid of Draconic Will by using Timeless to remove tons of conditions. Additionally if you ramp up your mana on spell crit some you may be able to do something like leverage Aegis instead of Unstoppable.
Edit2: This Aegis variation theme was originally something I was trying to make, but it was hard to get right and there were too many conccurent variables to juggle. So I opted for the "known" strategy of making a "magic marauder". I would still like to see something like this build using AM style defense instead of marauder. This build should be taken a reference. Ultimately I would like to see something in this vein that does not use Unstoppable. I may or may not invest the time into this. One of the main reason I opted for this build as first step is that winning in Madness is a fairly major investment and I wanted a godo ROI (return on investment).