That dashes any hope of secret grand juries in progress.
It shouldn't. Neither Trump nor the DoJ is neutered by having Sessions sit out a few classes of investigation and prosecution.
What does dash the hope is unwillingness on the part of the FBI to start or forward investigations of the politically connected to US Attorneys, and US Attorneys spiking those cases.
Trump: I will instruct my AG to appoint a SC to look into Hillary
The Second U.S. Presidential Debate - Oct 10, 2016
It is difficult (that's an understatement) to have one's own AG investigate oneself, or one's political opponent. Those endeavors inherently call for some sort of independent review. Trump seems to have understood this at least with regard to going after an opponent.
I know they can and will, but I ould like to see on here how the charter members of the Jeff Sessions Worship cult explains this: "Awhile back" is January 10, in his contentious confirmation hearing. GRASSLEY: During the course of the presidential campaign, you made a number of statements about the investigation of former Secretary of State Hillary Clinton, relating to her handling of sensitive e-mails and regarding certain actions of the Clinton Foundation. You weren't alone in that criticism. I was certainly critical in the same way as were millions of Americans on those matters, but now, you've been nominated to serve as attorney general. In light of those comments that you made, some have expressed concerns about whether you can approach the Clinton matter impartially in both fact and appearance. How do you plan to address those concerns? SESSIONS: Mr. Chairman, it was a highly contentious campaign. I, like a lot of people, made comments about the issues in that campaign. With regard to Secretary Clinton and some of the comments I made, I do believe that that could place me objectivity in question. I've given that thought. I believe the proper thing for me to do, would be to recuse myself from any questions involving those kind of investigations that involve Secretary Clinton and that were raised during the campaign or to be otherwise connected to it.