First and foremost, the mini missile pods are the worst against cyborgs, so I don't know where you are getting that notion from.
Experience, mostly. From my times actually using the things (I generally don't; they've got pretty low HP), they rip cyborgs about as quickly as equal-tech MGs and from further away, at least until assault guns roll around.
Also, rocket artillery has the longest range of ALL artillery, and has a good AOF, along with tons of damage. It just reloads terribly slow, and can easily miss at the longer ranges.
Yeah, I actually fielded some in a skirmish just now (well, 'just now' started two hours ago

). My previous reason for not using them stands, actually -- they don't do terribly much damage versus
tanks, at least compared to a groundshaker or hellstorm. That being said, once you get a few of them set up, they're absolutely ridiculous.
The range is a joke -- on the map I was playing, they very literally were hitting things on the other side of the map. A volley of five-six archangels will drop a bastion in one go, and if you've got
enough of them, they'll take out heavy tanks before the things get in range. But again, it takes more than one or two to pull it off, and those things are
not cheap, in any way, shape, or form. The tech is expensive and
way down the tech tree and the turret itself is bloody crazy from the cost perspective. Ripples aren't hanging quite so high on the cost tree, but they're still terribly expensive and, as you said, slow.
Basically, howitzers are generally going to be the better go-to artillery unless you're really freaking bloody sure you can set up and protect a rocket farm. Even then, if the enemy's doing something along the lines you prefer to do -- lots of comparatively weaker units -- an equal-cost amount of groundshakers are going to be preferable -- the GSs have over twice the splash radius.
Anyway, like most WZ, it's a trade-off. That being said, a critical mass of rocket arty is a helluva bigger threat than a critical mass of howitzers. Archangels hit from half-again as far away as GSs. Anyway, according to DPS, it's going to go something like ripple < howitzer line < archangels. Something to think about.