The question is how do you understand "God blessed"? I think you understand it as a verbal rather than God being described as blessed. Can you clarify this?
Originally I saw this as
God blessed (is Christ) for ever
based on the simple reading of the AV text.
Then I ran into a Greek-geek explanation from a gentleman named spin on the Bible Christian and History Forum.
θεος ευλογητος εις τους αιωνας
God blessed for ever
The last line is Greek working differently from English. We'd use a subordinate clause, "who God blessed forever." The Greek instead uses a verbal form as a noun, still with the subject "God" and tacks the whole nominalized sentence on. We might try "blessed by God forever". God is the one doing the blessing and the Christ is the one blessed. ....
On the text, the writer has placed two noun forms together, God and the nominalized verb ("blessed"), both nominative singular masculine, so you naturally link them together (just another indicator). But if you can propose a grammatical reason for separating the two NSMs and placing the first with a phrase it has no apparent grammatical connection with, I'll be willing to read it, but I won't hold my breath. Perhaps you might like to reorder ο ων επι παντων θεος as well to help you. I won't mind. Honest.