As shown (with no output load) the signal at Vout will not be affected much at all by your RC "equalizer". If you were to place a low value resistive load (maybe 100 ohms or lower) from Vout to ground you should then see a better response. If the added load doesn't give a satisfactory square wave then you might even consider placing a simple high speed comparator circuit after the AD8010. To limit the frequency response of the AD8010 (and reduce oscillations etc.) also consider placing a very small value capacitor across the 10k, (low pf range). The added capacitor would help to give a smooth pulse to the comparator,(if used), then the comparator can further square up the signal. In addition be sure to use bypass capacitors at all power pins.