What wattage bulbs? I think standard H4 are something like 55/50W, you can buy 100/90W I was considering one as my headlight is a bit pants too. Changing the colour of white can make an impact as well, I used to hate riding at night on my 125 and 250 with their crappy 35W standard yellowy white bulbs, I changed them to a much "whiter" light and the improvement was good.

Twitchy front may not be just tyres, could be suspension setup or even worn bearings.