There are many many mages that are ssssssssslowwww.
Their PD doesn't suck harder (at least not sensibly much) than machaka's one.
In fact their sacreds are almost the only troops I do recruit, with some decoys and archers, they have the upkeep of a chaff unit.(dom 6+)
You don't seem to consider the 3E and 3W mages you can easily enroll(and they often have 4), with great moral and I think 2 strategic movement. I wonder if you use the golem summons with MA Agartha.
Their starting army is utter crap ? Okay, use it to patrol on turn one, recruit sacreds, mix, attack : you'll beat anything not being heavy cavalry.
I find spiders as being costly to enroll, costly to maintain, and not effective enougth in effectively killing something. With bandar you can have many more effective combat groups, raiding behind ennemy lines.
I think a water 9 bless, plus whatever you like or can afford greatly reduces the archer vulnerability, and can easily be achieved with neutral or better scales (I'm at work, so I can't check). You don't need a combat pretender with your sacreds, so why not an dormant/imprisoned one ?
But I agree with you : Machaka truly needs some love, be it summons or whatever pleases KO.