It is the case though, that almost all spells do not reflect the effect of the rune in the tooltip.

As an example for "warp speed", when buffed without the "enhanced effect" rune, it gives 25% reduced cooldown on weapon attacks, and damage ofc.
When buffed with the rune, it is 35% less cooldown of attacks, and more damage than without the run.
(example base attack cd 6s, with warp speed and no rune 4.5s, with warp speed and rune 3.9s ==> 25% and 35% reduction without and with the rune)

This is very simple to test, therefore I accuse you all of not doing your part properly! ;)

...one thing that would be actually interesting to know, is how they calculate the buffs and effects into the final values,
I can tell you that for instance, fire form and warp speed do add up, in that you'll do more raw damage (I mean damage per hit) than with either one alone, both for all damage and fire damage (fire form has a different bonus to either), but the bonus of both combined is nowhere close to what it should be, no matter how you calculate it (additive or multiplicative).

This is also the case with fire forms incoming damage reduction and endurance, whereas using both is only marginally better than either one alone.