Given the massive changes underway, the Drakh impacts probably can't be understood until all the new weapon suites are confirmed. The balance on the GEG is a VERY touchy thing -- doing the Drakh last makes all the sense in the world. Beam used to be the bane of several Drakh ships; with that mitigated somewhat, a reassessment of the Drakh is fundamentally necessary.
I have heard rumors of a substitute to simulate the Dissipator system. If so, just like the Drakh, defensive balance is an EXTREMELY touchy subject, and they, too, should be done at the absolute last minute. Probably after the Drakh, acutally.
Vorlons were fundamentally affected by the Beam system change. I actually wouldn't mind keeping both beam mechanics, and leaving the old "Oh My God beam system" mechanic vs. Hull 4 for ancient beam systems. They're certainly nasty enough. Maybe some hybrid. But the Vorlons, now, vs Hull 4 ships, have a huge problem, and it'll take some very Jack-Hanley deep thoughts to consider, well, just what their indentity should be.