Are we talking about the same thing? The "covenants" of covenant theology are not the covenants outlined in the OT: Abrahamic, Noaic, Mosaic, etc., whereas CT is based on presumed covenants of works and grace, and sometimes a third one, the covenant of redemption. The Biblical covenants are not the backbone of CT.
Concerning your description of dispensationalism, that's not what I teach. In dispensationalism, God does not "chop up God's redemption into parts." Rather, I teach that dispensationalism describes salvation history. Again, I have never thought that "God changes his methods over time." Is it possible that you abandoned dispensationalism because you didn't understand it? (Just suggesting.)
I see no connection between dispensationalism and the Cal/Arm debate. In fact, on the dispensational side you have no less than men like Lewis Sperry Chafer (4 point), John MacArthur (5 point), and the entire faculty of Detroit Baptist Theological Seminary. I also fail to see the connection between "150 years old" and anything else. Theology should not be delineated by its age, or we'd all be locked into the faulty theology of the "Didache."
As for the rest of your post, I'm mystified. Dispensationalism as legalism? "Entrenched on the throne of their life"? This further convinces me that you don't understand genuine dispensationalism. Have you ever read Ryrie's Dispensationalism?
I am definitely not a pure dispensationalist, but your objection to the "covenants" in covenant theology is spot on. IMO, there is no basis for assuming any sort of extra-biblical theological covenant. The covenants in Scripture make sense without needing to postulate a "covenant of grace," for instance.
I do think much of the heat thrown toward dispensationalism is backlash against a very strong (at times obsessive) focus on eschatology by some very vocal dispensationalists, but we shouldn't necessarily judge a theological framework by its loudest voices.