Deus enim rorem in illas misit,
de quo multiplex fama crevit,
ita quod omnes populi ex hac honorabili fama
velut cibum gustabant.
Then, to sum it,
you took the ita quod omnes populi ex hac honorabili fama velut cibum gustabant
as explaining how the word multiplex
it was so (= multiplex) in the manner that all the nations were tasting...
while I took it as explaining / supplementing the whole Deus rorem in illas misit, de quo multiplex fama crevit
it was so (= Deus rorem in illas...) that all the nations were going to taste...
I can't decide which is right. Yours seems right, too.
As to the imperfect as expressing a future in the past (e.g. was going to...),
I can't exactly rememer where it was written, and since I'm bad at searching the net I can't find the e-text page soon,
but I got to know the usage reading A New Latin Syntax
by E.C. Woodcock
If you don't find it yourself, I will see the book and find a passage telling about that imperfect usage, though it will take some time.
I got it.
For example, section 200 (ii) :
The imperfect tense is often used of a movement attempted or begun, but not finished.
e.g. Cic. Lig. 24 veniebatis in Africam.... prohibiti estis in provincia pedem ponere.
you were for coming into Africa, but you were prevented from setting foot in the province.
Livy, 7,17,12 orta contentio est quod duo patricii consules creabantur.
A dispute arose because movement was afoot to elect two patrician consuls.
In this conative or inceptive sense faciebam is almost equivalent to facturus eram, and accordingly the imperfect indicative, like -urus eram, is sometimes found in the apodosis of unreal conditions..................