When a pan does not heat properly, or get hot enough, that is made for induction tops it's normally because the bottom is warped. Warping is normally caused by taking the pan off of extreme heats and rushing it to the water faucet to cool it down, when one should try to put it out side on a block of wood, or the like. There are alot of methods people use to season(oil) the insides of their pans. As Paul said, stir frys are just that. Quick cooking, not elongated processes. Cutting your veggies to a fine julienne, will mean a quick toss in, a bit soft fried outside texture, and inside crunchiness, or mush if you prefer.
The only time I can imagine a veg in a wok should be blackened is with Soy or Oyster Sauce. Or a nice Thai Brown Gravy.
There are some woks that are a 100% curve on the bottom, but they should be used for a professional wok well. Or, as I think of it, there ARE induction wok cookers. The Seehotel in Horgen, on the top floor, in the restaurant there I have seen professional wok only induction tops. If you want to be a food tourist.