Why such large gate resistors on the mosfets? Something in the single or low double-digit range (like 4.7 to 22 Ω) may help, if ringing doesn't become a problem. Also, at higher currents, the current gain from the 2N3904's may not be enough to drive the mosfets quickly. 2N2222's will give you more current. In either case, you may want to reduce the base resistor. How much can the MCU output per pin? (I am more familiar with Microchip PIC's.)
John