So what will Espada's new role in the Senate be?

In addition to other changes, and as announced in their press conference, the Senate's new rules provide for power sharing between the Temporary President (Senator Pedro Espada) and the Majority Leader (Dean Skelos). But sharing doesn't mean EQUAL sharing. Espada does not have many of the powers Temporary Presidents have been given in the past.

While many decisions previously subject to the approval of the Majority Leader – like referring bills to committees and putting bills on the active list – are now subject to both the Majority Leader and the Temporary President, many of the important responsibilities allocated to the Temporary President (who traditionally also holds the position of Majority Leader) under the old rules have been explicitly shifted to the Majority Leader in the new resolution. Dean Skelos will appoint committee chairs, appoint the chair of the Rules committee, appoint officers and employees of the senate, and have general control of the chamber.

If this was a power grab on the part of Pedro Espada, he may not have too much power to show for it (at least as relates to the operation of the Senate chamber).