If the Russians take Kharkov/Kharkiev relatively quickly or they fail sets the stage for this summer.
If Kharkov is taken look at the south and keep your eye on Odessa and see if Russia makes a move in that direction or continues on to start hitting Kiev.
If the Russians fail to take Kharkov or it takes several months and cost them a lot of men and equipment, then any further major advances will not happen this year and could change what Russia might be willing to settle for in any negotiation that takes place in the future.
I think the Ukes are going on whatever offensive they can muster on the Russian bank of the Dnieper around Krynki. My fear, until Tuesday, was a NATO Inchon type landing in this area.